diff --git a/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/accept/ApSendAcceptService.kt b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/accept/ApSendAcceptService.kt
new file mode 100644
index 00000000..59f4f4ec
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/accept/ApSendAcceptService.kt
@@ -0,0 +1,16 @@
+package dev.usbharu.hideout.activitypub.service.activity.accept
+
+import dev.usbharu.hideout.core.domain.model.user.User
+import org.springframework.stereotype.Service
+
+interface ApSendAcceptService {
+    suspend fun sendAccept(user: User, target: User)
+}
+
+@Service
+class ApSendAcceptServiceImpl : ApSendAcceptService {
+    override suspend fun sendAccept(user: User, target: User) {
+        TODO("Not yet implemented")
+    }
+
+}
diff --git a/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/block/APSendBlockService.kt b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/block/APSendBlockService.kt
new file mode 100644
index 00000000..f814da7e
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/block/APSendBlockService.kt
@@ -0,0 +1,43 @@
+package dev.usbharu.hideout.activitypub.service.activity.block
+
+import dev.usbharu.hideout.activitypub.domain.model.Block
+import dev.usbharu.hideout.activitypub.domain.model.Follow
+import dev.usbharu.hideout.activitypub.domain.model.Reject
+import dev.usbharu.hideout.application.config.ApplicationConfig
+import dev.usbharu.hideout.core.domain.model.user.User
+import dev.usbharu.hideout.core.external.job.DeliverBlockJob
+import dev.usbharu.hideout.core.external.job.DeliverBlockJobParam
+import dev.usbharu.hideout.core.service.job.JobQueueParentService
+import org.springframework.stereotype.Service
+
+interface APSendBlockService {
+    suspend fun sendBlock(user: User, target: User)
+}
+
+@Service
+class ApSendBlockServiceImpl(
+    private val applicationConfig: ApplicationConfig,
+    private val jobQueueParentService: JobQueueParentService,
+    private val deliverBlockJob: DeliverBlockJob
+) : APSendBlockService {
+    override suspend fun sendBlock(user: User, target: User) {
+        val blockJobParam = DeliverBlockJobParam(
+            user.id,
+            Block(
+                user.url,
+                "${applicationConfig.url}/block/${user.id}/${target.id}",
+                target.url
+            ),
+            Reject(
+                user.url,
+                "${applicationConfig.url}/reject/${user.id}/${target.id}",
+                Follow(
+                    apObject = user.url,
+                    actor = target.url
+                )
+            ),
+            target.inbox
+        )
+        jobQueueParentService.scheduleTypeSafe(deliverBlockJob, blockJobParam)
+    }
+}
diff --git a/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/reject/ApSendRejectService.kt b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/reject/ApSendRejectService.kt
new file mode 100644
index 00000000..29c66e28
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/reject/ApSendRejectService.kt
@@ -0,0 +1,7 @@
+package dev.usbharu.hideout.activitypub.service.activity.reject
+
+import dev.usbharu.hideout.core.domain.model.user.User
+
+interface ApSendRejectService {
+    suspend fun sendReject(user: User, target: User)
+}
diff --git a/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/undo/APSendUndoService.kt b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/undo/APSendUndoService.kt
new file mode 100644
index 00000000..827b186e
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/activity/undo/APSendUndoService.kt
@@ -0,0 +1,8 @@
+package dev.usbharu.hideout.activitypub.service.activity.undo
+
+import dev.usbharu.hideout.core.domain.model.user.User
+
+interface APSendUndoService {
+    suspend fun sendUndoFollow(user: User, target: User)
+    suspend fun sendUndoBlock(user: User, target: User)
+}
diff --git a/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/Relationship.kt b/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/Relationship.kt
new file mode 100644
index 00000000..51a3da60
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/Relationship.kt
@@ -0,0 +1,22 @@
+package dev.usbharu.hideout.core.domain.model.relationship
+
+/**
+ * ユーザーとの関係を表します
+ *
+ * @property userId ユーザー
+ * @property targetUserId 相手ユーザー
+ * @property following フォローしているか
+ * @property blocking ブロックしているか
+ * @property muting ミュートしているか
+ * @property followRequest フォローリクエストを送っているか
+ * @property ignoreFollowRequestFromTarget フォローリクエストを無視しているか
+ */
+data class Relationship(
+    val userId: Long,
+    val targetUserId: Long,
+    val following: Boolean,
+    val blocking: Boolean,
+    val muting: Boolean,
+    val followRequest: Boolean,
+    val ignoreFollowRequestFromTarget: Boolean
+)
diff --git a/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/RelationshipRepository.kt b/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/RelationshipRepository.kt
new file mode 100644
index 00000000..4b3fc6bc
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/core/domain/model/relationship/RelationshipRepository.kt
@@ -0,0 +1,31 @@
+package dev.usbharu.hideout.core.domain.model.relationship
+
+/**
+ * [Relationship]の永続化
+ *
+ */
+interface RelationshipRepository {
+    /**
+     * 永続化します
+     *
+     * @param relationship 永続化する[Relationship]
+     * @return 永続化された[Relationship]
+     */
+    suspend fun save(relationship: Relationship): Relationship
+
+    /**
+     * 永続化されたものを削除します
+     *
+     * @param relationship 削除する[Relationship]
+     */
+    suspend fun delete(relationship: Relationship)
+
+    /**
+     * userIdとtargetUserIdで[Relationship]を取得します
+     *
+     * @param userId 取得するユーザーID
+     * @param targetUserId 対象ユーザーID
+     * @return 取得された[Relationship] 存在しない場合nullが返ります
+     */
+    suspend fun findByUserIdAndTargetUserId(userId: Long, targetUserId: Long): Relationship?
+}
diff --git a/src/main/kotlin/dev/usbharu/hideout/core/service/relationship/RelationshipService.kt b/src/main/kotlin/dev/usbharu/hideout/core/service/relationship/RelationshipService.kt
new file mode 100644
index 00000000..4f0a164a
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/core/service/relationship/RelationshipService.kt
@@ -0,0 +1,14 @@
+package dev.usbharu.hideout.core.service.relationship
+
+interface RelationshipService {
+    suspend fun followRequest(userId: Long, targetId: Long)
+    suspend fun block(userId: Long, targetId: Long)
+    suspend fun acceptFollowRequest(userId: Long, targetId: Long)
+    suspend fun rejectFollowRequest(userId: Long, targetId: Long)
+    suspend fun ignoreFollowRequest(userId: Long, targetId: Long)
+    suspend fun unfollow(userId: Long, targetId: Long)
+    suspend fun unblock(userId: Long, targetId: Long)
+    suspend fun mute(userId: Long, targetId: Long)
+    suspend fun unmute(userId: Long, targetId: Long)
+
+}
diff --git a/src/main/kotlin/dev/usbharu/hideout/core/service/relationship/RelationshipServiceImpl.kt b/src/main/kotlin/dev/usbharu/hideout/core/service/relationship/RelationshipServiceImpl.kt
new file mode 100644
index 00000000..1ee53312
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/core/service/relationship/RelationshipServiceImpl.kt
@@ -0,0 +1,266 @@
+package dev.usbharu.hideout.core.service.relationship
+
+import dev.usbharu.hideout.activitypub.service.activity.accept.ApSendAcceptService
+import dev.usbharu.hideout.activitypub.service.activity.block.APSendBlockService
+import dev.usbharu.hideout.activitypub.service.activity.follow.APSendFollowService
+import dev.usbharu.hideout.activitypub.service.activity.reject.ApSendRejectService
+import dev.usbharu.hideout.activitypub.service.activity.undo.APSendUndoService
+import dev.usbharu.hideout.application.config.ApplicationConfig
+import dev.usbharu.hideout.core.domain.exception.FailedToGetResourcesException
+import dev.usbharu.hideout.core.domain.model.relationship.Relationship
+import dev.usbharu.hideout.core.domain.model.relationship.RelationshipRepository
+import dev.usbharu.hideout.core.domain.model.user.User
+import dev.usbharu.hideout.core.query.UserQueryService
+import dev.usbharu.hideout.core.service.follow.SendFollowDto
+import org.slf4j.LoggerFactory
+import org.springframework.stereotype.Service
+
+@Service
+class RelationshipServiceImpl(
+    private val applicationConfig: ApplicationConfig,
+    private val userQueryService: UserQueryService,
+    private val relationshipRepository: RelationshipRepository,
+    private val apSendFollowService: APSendFollowService,
+    private val apSendBlockService: APSendBlockService,
+    private val apSendAcceptService: ApSendAcceptService,
+    private val apSendRejectService: ApSendRejectService,
+    private val apSendUndoService: APSendUndoService
+) : RelationshipService {
+    override suspend fun followRequest(userId: Long, targetId: Long) {
+        val relationship =
+            relationshipRepository.findByUserIdAndTargetUserId(userId, targetId)?.copy(followRequest = true)
+                ?: Relationship(
+                    userId = userId,
+                    targetUserId = targetId,
+                    following = false,
+                    blocking = false,
+                    muting = false,
+                    followRequest = true,
+                    ignoreFollowRequestFromTarget = false
+                )
+
+        val inverseRelationship = relationshipRepository.findByUserIdAndTargetUserId(targetId, userId) ?: Relationship(
+            userId = targetId,
+            targetUserId = userId,
+            following = false,
+            blocking = false,
+            muting = false,
+            followRequest = false,
+            ignoreFollowRequestFromTarget = false
+        )
+
+        if (inverseRelationship.blocking) {
+            logger.debug("FAILED Blocked by target. userId: {} targetId: {}", userId, targetId)
+            return
+        }
+
+        if (relationship.blocking) {
+            logger.debug("FAILED Blocking user. userId: {} targetId: {}", userId, targetId)
+            return
+        }
+        if (inverseRelationship.ignoreFollowRequestFromTarget) {
+            logger.debug("SUCCESS Ignore Follow Request. userId: {} targetId: {}", userId, targetId)
+            return
+        }
+
+
+        relationshipRepository.save(relationship)
+
+        val remoteUser = isRemoteUser(targetId)
+
+        if (remoteUser != null) {
+            val user = userQueryService.findById(userId)
+            apSendFollowService.sendFollow(SendFollowDto(user, remoteUser))
+        } else {
+            //TODO: フォロー許可制ユーザーを実装したら消す
+            acceptFollowRequest(userId, targetId)
+        }
+
+    }
+
+    override suspend fun block(userId: Long, targetId: Long) {
+        val relationship = relationshipRepository.findByUserIdAndTargetUserId(userId, targetId)
+            ?.copy(blocking = true, followRequest = false, following = false) ?: Relationship(
+            userId = userId,
+            targetUserId = targetId,
+            following = false,
+            blocking = true,
+            muting = false,
+            followRequest = false,
+            ignoreFollowRequestFromTarget = false
+        )
+
+        relationshipRepository.save(relationship)
+
+        val remoteUser = isRemoteUser(targetId)
+
+        if (remoteUser != null) {
+            val user = userQueryService.findById(userId)
+            apSendBlockService.sendBlock(user, remoteUser)
+        }
+    }
+
+    override suspend fun acceptFollowRequest(userId: Long, targetId: Long) {
+        val relationship = relationshipRepository.findByUserIdAndTargetUserId(userId, targetId)
+
+        if (relationship == null) {
+            logger.warn("FAILED Follow Request Not Found. (Relationship) userId: {} targetId: {}", userId, targetId)
+            return
+        }
+
+        if (relationship.followRequest.not()) {
+            logger.warn("FAILED Follow Request Not Found. (Follow Request) userId: {} targetId: {}", userId, targetId)
+            return
+        }
+
+        if (relationship.blocking) {
+            logger.warn("FAILED Blocking user userId: {} targetId: {}", userId, targetId)
+            throw IllegalStateException("Cannot accept a follow request from a blocked user. userId: $userId targetId: $targetId")
+        }
+
+        val copy = relationship.copy(followRequest = false, following = true, blocking = false)
+
+        relationshipRepository.save(copy)
+
+        val remoteUser = isRemoteUser(targetId)
+
+        if (remoteUser != null) {
+            val user = userQueryService.findById(userId)
+            apSendAcceptService.sendAccept(user, remoteUser)
+        }
+    }
+
+    override suspend fun rejectFollowRequest(userId: Long, targetId: Long) {
+        val relationship = relationshipRepository.findByUserIdAndTargetUserId(userId, targetId)
+
+        if (relationship == null) {
+            logger.warn("FAILED Follow Request Not Found. (Relationship) userId: {} targetId: {}", userId, targetId)
+            return
+        }
+
+        if (relationship.followRequest.not()) {
+            logger.warn("FAILED Follow Request Not Found. (Follow Request) userId: {} targetId: {}", userId, targetId)
+            return
+        }
+
+        val copy = relationship.copy(followRequest = false, following = false, blocking = false)
+
+        relationshipRepository.save(copy)
+
+        val remoteUser = isRemoteUser(targetId)
+
+        if (remoteUser != null) {
+            val user = userQueryService.findById(userId)
+            apSendRejectService.sendReject(user, remoteUser)
+        }
+    }
+
+    override suspend fun ignoreFollowRequest(userId: Long, targetId: Long) {
+        val relationship = relationshipRepository.findByUserIdAndTargetUserId(userId, targetId)
+            ?.copy(ignoreFollowRequestFromTarget = true)
+            ?: Relationship(
+                userId = userId,
+                targetUserId = targetId,
+                following = false,
+                blocking = false,
+                muting = false,
+                followRequest = false,
+                ignoreFollowRequestFromTarget = true
+            )
+
+        relationshipRepository.save(relationship)
+    }
+
+    override suspend fun unfollow(userId: Long, targetId: Long) {
+        val relationship = relationshipRepository.findByUserIdAndTargetUserId(userId, targetId)
+
+        if (relationship == null) {
+            logger.warn("FAILED Unfollow. (Relationship) userId: {} targetId: {}", userId, targetId)
+            return
+        }
+
+        if (relationship.following.not()) {
+            logger.warn("SUCCESS User already unfollow. userId: {} targetId: {}", userId, targetId)
+            return
+        }
+
+        val copy = relationship.copy(following = false)
+
+        relationshipRepository.save(copy)
+
+        val remoteUser = isRemoteUser(targetId)
+
+        if (remoteUser != null) {
+            val user = userQueryService.findById(userId)
+            apSendUndoService.sendUndoFollow(user, remoteUser)
+        }
+    }
+
+    override suspend fun unblock(userId: Long, targetId: Long) {
+        val relationship = relationshipRepository.findByUserIdAndTargetUserId(userId, targetId)
+
+        if (relationship == null) {
+            logger.warn("FAILED Unblock. (Relationship) userId: {} targetId: {}", userId, targetId)
+            return
+        }
+
+        if (relationship.blocking.not()) {
+            logger.warn("SUCCESS User is not blocking. userId: {] targetId: {}", userId, targetId)
+            return
+        }
+
+        val copy = relationship.copy(blocking = false)
+        relationshipRepository.save(copy)
+
+
+        val remoteUser = isRemoteUser(targetId)
+        if (remoteUser == null) {
+            val user = userQueryService.findById(userId)
+            apSendUndoService.sendUndoBlock(user, targetId)
+        }
+    }
+
+    override suspend fun mute(userId: Long, targetId: Long) {
+        val relationship = relationshipRepository.findByUserIdAndTargetUserId(userId, targetId)?.copy(muting = true)
+            ?: Relationship(
+                userId = userId,
+                targetUserId = targetId,
+                following = false,
+                blocking = false,
+                muting = true,
+                followRequest = false,
+                ignoreFollowRequestFromTarget = false
+            )
+
+        relationshipRepository.save(relationship)
+    }
+
+    override suspend fun unmute(userId: Long, targetId: Long) {
+        val relationship = relationshipRepository.findByUserIdAndTargetUserId(userId, targetId)?.copy(muting = false)
+
+        if (relationship == null) {
+            logger.warn("FAILED Mute. (Relationship) userId: {} targetId: {}", userId, targetId)
+            return
+        }
+
+        relationshipRepository.save(relationship)
+    }
+
+    private suspend fun isRemoteUser(userId: Long): User? {
+        val user = try {
+            userQueryService.findById(userId)
+        } catch (e: FailedToGetResourcesException) {
+            logger.warn("User not found.", e)
+            throw IllegalStateException("User not found.", e)
+        }
+
+        if (user.domain == applicationConfig.url.host) {
+            return null
+        }
+        return user
+    }
+
+    companion object {
+        private val logger = LoggerFactory.getLogger(RelationshipServiceImpl::class.java)
+    }
+}