diff --git a/src/main/kotlin/dev/usbharu/hideout/application/config/SecurityConfig.kt b/src/main/kotlin/dev/usbharu/hideout/application/config/SecurityConfig.kt
index eb19802f..e42ad9b9 100644
--- a/src/main/kotlin/dev/usbharu/hideout/application/config/SecurityConfig.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/application/config/SecurityConfig.kt
@@ -197,6 +197,7 @@ class SecurityConfig {
                 authorize(GET, "/api/v1/accounts/*", permitAll)
                 authorize(GET, "/api/v1/accounts/*/statuses", permitAll)
                 authorize(POST, "/api/v1/accounts/*/follow", hasAnyScope("write", "write:follows"))
+                authorize(POST, "/api/v1/accounts/*/block", hasAnyScope("write", "write:blocks"))
 
                 authorize(POST, "/api/v1/media", hasAnyScope("write", "write:media"))
                 authorize(POST, "/api/v1/statuses", hasAnyScope("write", "write:statuses"))
diff --git a/src/main/kotlin/dev/usbharu/hideout/core/service/block/BlockServiceImpl.kt b/src/main/kotlin/dev/usbharu/hideout/core/service/block/BlockServiceImpl.kt
index bc0eef96..77209855 100644
--- a/src/main/kotlin/dev/usbharu/hideout/core/service/block/BlockServiceImpl.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/core/service/block/BlockServiceImpl.kt
@@ -28,7 +28,7 @@ class BlockServiceImpl(
     private val applicationConfig: ApplicationConfig
 ) :
     BlockService {
-    override suspend fun block(userId: Long, target: Long): Unit = transaction.transaction {
+    override suspend fun block(userId: Long, target: Long) {
         logger.debug("Block userId: {} → target: {}", userId, target)
         blockRepository.save(Block(userId, target))
         if (followerQueryService.alreadyFollow(userId, target)) {
@@ -39,13 +39,13 @@ class BlockServiceImpl(
         val user = userRepository.findById(userId) ?: throw IllegalStateException("Block user was not found.")
 
         if (user.domain == applicationConfig.url.host) {
-            return@transaction
+            return
         }
 
         val target = userRepository.findById(target) ?: throw IllegalStateException("Block use was not found.")
 
         if (target.domain == applicationConfig.url.host) {
-            return@transaction
+            return
         }
 
         val blockJobParam = DeliverBlockJobParam(
diff --git a/src/main/kotlin/dev/usbharu/hideout/mastodon/interfaces/api/account/MastodonAccountApiController.kt b/src/main/kotlin/dev/usbharu/hideout/mastodon/interfaces/api/account/MastodonAccountApiController.kt
index a7f3741c..0ebed08e 100644
--- a/src/main/kotlin/dev/usbharu/hideout/mastodon/interfaces/api/account/MastodonAccountApiController.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/mastodon/interfaces/api/account/MastodonAccountApiController.kt
@@ -103,4 +103,14 @@ class MastodonAccountApiController(
                 .asFlow()
         )
     }
+
+    override suspend fun apiV1AccountsIdBlockPost(id: String): ResponseEntity<Relationship> {
+        val principal = SecurityContextHolder.getContext().getAuthentication().principal as Jwt
+
+        val userid = principal.getClaim<String>("uid").toLong()
+
+        val block = accountApiService.block(userid, id.toLong())
+
+        return ResponseEntity.ok(block)
+    }
 }
diff --git a/src/main/kotlin/dev/usbharu/hideout/mastodon/service/account/AccountApiService.kt b/src/main/kotlin/dev/usbharu/hideout/mastodon/service/account/AccountApiService.kt
index a3315107..2e9f76f4 100644
--- a/src/main/kotlin/dev/usbharu/hideout/mastodon/service/account/AccountApiService.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/mastodon/service/account/AccountApiService.kt
@@ -1,8 +1,11 @@
 package dev.usbharu.hideout.mastodon.service.account
 
 import dev.usbharu.hideout.application.external.Transaction
+import dev.usbharu.hideout.core.domain.exception.FailedToGetResourcesException
+import dev.usbharu.hideout.core.domain.model.block.BlockRepository
 import dev.usbharu.hideout.core.domain.model.user.UserRepository
 import dev.usbharu.hideout.core.query.FollowerQueryService
+import dev.usbharu.hideout.core.service.block.BlockService
 import dev.usbharu.hideout.core.service.user.UserCreateDto
 import dev.usbharu.hideout.core.service.user.UserService
 import dev.usbharu.hideout.domain.mastodon.model.generated.*
@@ -32,6 +35,7 @@ interface AccountApiService {
     suspend fun follow(userid: Long, followeeId: Long): Relationship
     suspend fun account(id: Long): Account
     suspend fun relationships(userid: Long, id: List<Long>, withSuspended: Boolean): List<Relationship>
+    suspend fun block(userid: Long, target: Long): Relationship
 }
 
 @Service
@@ -41,7 +45,9 @@ class AccountApiServiceImpl(
     private val userService: UserService,
     private val followerQueryService: FollowerQueryService,
     private val userRepository: UserRepository,
-    private val statusQueryService: StatusQueryService
+    private val statusQueryService: StatusQueryService,
+    private val blockService: BlockService,
+    private val blockRepository: BlockRepository
 ) :
     AccountApiService {
     override suspend fun accountsStatuses(
@@ -160,6 +166,35 @@ class AccountApiServiceImpl(
             }
         }
 
+    override suspend fun block(userid: Long, target: Long): Relationship = transaction.transaction {
+        blockService.block(userid, target)
+
+        val blocked = try {
+            blockRepository.findByUserIdAndTarget(target, userid)
+            true
+        } catch (e: FailedToGetResourcesException) {
+            false
+        }
+
+        val requested = userRepository.findFollowRequestsById(target, userid)
+
+        Relationship(
+            target.toString(),
+            false,
+            true,
+            false,
+            false,
+            true,
+            blocked,
+            false,
+            false,
+            requested,
+            false,
+            false,
+            ""
+        )
+    }
+
     private fun from(account: Account): CredentialAccount {
         return CredentialAccount(
             id = account.id,
diff --git a/src/main/resources/openapi/mastodon.yaml b/src/main/resources/openapi/mastodon.yaml
index 3049c1d9..592726ae 100644
--- a/src/main/resources/openapi/mastodon.yaml
+++ b/src/main/resources/openapi/mastodon.yaml
@@ -287,6 +287,27 @@ paths:
               schema:
                 $ref: "#/components/schemas/Relationship"
 
+  /api/v1/accounts/{id}/block:
+    post:
+      tags:
+        - account
+      security:
+        - OAuth2:
+            - "write:blocks"
+      parameters:
+        - in: path
+          name: id
+          required: true
+          schema:
+            type: string
+      responses:
+        200:
+          description: 成功
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Relationship"
+
   /api/v1/accounts/{id}/statuses:
     get:
       tags: