diff --git a/src/main/kotlin/dev/usbharu/hideout/core/domain/model/reaction/ReactionRepository.kt b/src/main/kotlin/dev/usbharu/hideout/core/domain/model/reaction/ReactionRepository.kt
index 8005bbd2..4d3964eb 100644
--- a/src/main/kotlin/dev/usbharu/hideout/core/domain/model/reaction/ReactionRepository.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/core/domain/model/reaction/ReactionRepository.kt
@@ -11,10 +11,13 @@ interface ReactionRepository {
     suspend fun delete(reaction: Reaction): Reaction
     suspend fun deleteByPostId(postId: Long): Int
     suspend fun deleteByActorId(actorId: Long): Int
+    suspend fun deleteByPostIdAndActorId(postId: Long, actorId: Long)
+    suspend fun deleteByPostIdAndActorIdAndEmoji(postId: Long, actorId: Long, emoji: Emoji)
     suspend fun findByPostId(postId: Long): List<Reaction>
     suspend fun findByPostIdAndActorIdAndEmojiId(postId: Long, actorId: Long, emojiId: Long): Reaction?
     suspend fun existByPostIdAndActorIdAndEmojiId(postId: Long, actorId: Long, emojiId: Long): Boolean
     suspend fun existByPostIdAndActorIdAndUnicodeEmoji(postId: Long, actorId: Long, unicodeEmoji: String): Boolean
     suspend fun existByPostIdAndActorIdAndEmoji(postId: Long, actorId: Long, emoji: Emoji): Boolean
+    suspend fun existByPostIdAndActor(postId: Long, actorId: Long): Boolean
     suspend fun findByPostIdAndActorId(postId: Long, actorId: Long): List<Reaction>
 }
diff --git a/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/ReactionRepositoryImpl.kt b/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/ReactionRepositoryImpl.kt
index 6847ab14..b932a54f 100644
--- a/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/ReactionRepositoryImpl.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/core/infrastructure/exposedrepository/ReactionRepositoryImpl.kt
@@ -79,6 +79,29 @@ class ReactionRepositoryImpl(
         }
     }
 
+    override suspend fun deleteByPostIdAndActorId(postId: Long, actorId: Long): Unit = query {
+        Reactions.deleteWhere {
+            Reactions.postId eq postId and (Reactions.actorId eq actorId)
+        }
+    }
+
+    override suspend fun deleteByPostIdAndActorIdAndEmoji(postId: Long, actorId: Long, emoji: Emoji): Unit = query {
+        if (emoji is CustomEmoji) {
+            Reactions.deleteWhere {
+                Reactions.postId.eq(postId)
+                    .and(Reactions.actorId.eq(actorId))
+                    .and(Reactions.customEmojiId.eq(emoji.id))
+            }
+        } else {
+            Reactions.deleteWhere {
+                Reactions.postId.eq(postId)
+                    .and(Reactions.actorId.eq(actorId))
+                    .and(Reactions.unicodeEmoji.eq(emoji.name))
+            }
+        }
+
+    }
+
     override suspend fun findByPostId(postId: Long): List<Reaction> = query {
         return@query Reactions.leftJoin(CustomEmojis).select { Reactions.postId eq postId }.map { it.toReaction() }
     }
@@ -135,6 +158,12 @@ class ReactionRepositoryImpl(
         return@query query.empty().not()
     }
 
+    override suspend fun existByPostIdAndActor(postId: Long, actorId: Long): Boolean = query {
+        Reactions.select {
+            Reactions.postId.eq(postId).and(Reactions.actorId.eq(actorId))
+        }.empty().not()
+    }
+
     override suspend fun findByPostIdAndActorId(postId: Long, actorId: Long): List<Reaction> = query {
         return@query Reactions.leftJoin(CustomEmojis)
             .select { Reactions.postId eq postId and (Reactions.actorId eq actorId) }
diff --git a/src/main/kotlin/dev/usbharu/hideout/core/service/reaction/ReactionServiceImpl.kt b/src/main/kotlin/dev/usbharu/hideout/core/service/reaction/ReactionServiceImpl.kt
index 0d623846..927dd9fb 100644
--- a/src/main/kotlin/dev/usbharu/hideout/core/service/reaction/ReactionServiceImpl.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/core/service/reaction/ReactionServiceImpl.kt
@@ -1,10 +1,10 @@
 package dev.usbharu.hideout.core.service.reaction
 
 import dev.usbharu.hideout.activitypub.service.activity.like.APReactionService
+import dev.usbharu.hideout.core.domain.exception.resource.DuplicateException
 import dev.usbharu.hideout.core.domain.model.emoji.Emoji
 import dev.usbharu.hideout.core.domain.model.reaction.Reaction
 import dev.usbharu.hideout.core.domain.model.reaction.ReactionRepository
-import org.jetbrains.exposed.exceptions.ExposedSQLException
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 import org.springframework.stereotype.Service
@@ -19,13 +19,12 @@ class ReactionServiceImpl(
         actorId: Long,
         postId: Long
     ) {
-        if (reactionRepository.existByPostIdAndActorIdAndEmoji(postId, actorId, emoji).not()) {
-            try {
-                reactionRepository.save(
-                    Reaction(reactionRepository.generateId(), emoji, postId, actorId)
-                )
-            } catch (_: ExposedSQLException) {
-            }
+        if (reactionRepository.existByPostIdAndActor(postId, actorId)) {
+            reactionRepository.deleteByPostIdAndActorId(postId, actorId)
+        }
+        try {
+            reactionRepository.save(Reaction(reactionRepository.generateId(), emoji, postId, actorId))
+        } catch (_: DuplicateException) {
         }
     }
 
diff --git a/src/main/resources/db/migration/V1__Init_DB.sql b/src/main/resources/db/migration/V1__Init_DB.sql
index e331c9f8..2e9e638b 100644
--- a/src/main/resources/db/migration/V1__Init_DB.sql
+++ b/src/main/resources/db/migration/V1__Init_DB.sql
@@ -131,11 +131,12 @@ alter table posts_emojis
 
 create table if not exists reactions
 (
-    id              bigserial primary key,
+    id       bigint primary key,
     unicode_emoji   varchar(255) null default null,
     custom_emoji_id bigint       null default null,
     post_id         bigint       not null,
-    actor_id        bigint       not null
+    actor_id bigint not null,
+    unique (post_id, actor_id)
 );
 alter table reactions
     add constraint fk_reactions_post_id__id foreign key (post_id) references posts (id) on delete restrict on update restrict;