diff --git a/packages/backend/src/server/api/endpoints/following/invalidate.ts b/packages/backend/src/server/api/endpoints/following/invalidate.ts
index 979d298f7d..01ccc2761b 100644
--- a/packages/backend/src/server/api/endpoints/following/invalidate.ts
+++ b/packages/backend/src/server/api/endpoints/following/invalidate.ts
@@ -69,12 +69,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check not following
-	const exist = await Followings.findOneBy({
-		followerId: follower.id,
-		followeeId: followee.id,
+	const exist = await Followings.exist({
+		where: {
+			followerId: follower.id,
+			followeeId: followee.id,
+		},
 	});
 
-	if (exist == null) {
+	if (!exist) {
 		throw new ApiError(meta.errors.notFollowing);
 	}
 
diff --git a/packages/backend/src/server/api/endpoints/renote-mute/create.ts b/packages/backend/src/server/api/endpoints/renote-mute/create.ts
index 857cbd9756..f09f197c01 100644
--- a/packages/backend/src/server/api/endpoints/renote-mute/create.ts
+++ b/packages/backend/src/server/api/endpoints/renote-mute/create.ts
@@ -47,12 +47,14 @@ export default define(meta, paramDef, async (ps, user) => {
 	});
 
 	// Check if already muting
-	const exist = await RenoteMutings.findOneBy({
-		muterId: muter.id,
-		muteeId: mutee.id,
+	const exist = await RenoteMutings.exist({
+		where: {
+			muterId: muter.id,
+			muteeId: mutee.id,
+		},
 	});
 
-	if (exist != null) {
+	if (exist) {
 		throw new ApiError(meta.errors.alreadyMuting);
 	}
 
diff --git a/packages/backend/src/services/note/unread.ts b/packages/backend/src/services/note/unread.ts
index 275b230d47..cb87abe0e6 100644
--- a/packages/backend/src/services/note/unread.ts
+++ b/packages/backend/src/services/note/unread.ts
@@ -42,9 +42,9 @@ export async function insertNoteUnread(
 
 	// 2秒経っても既読にならなかったら「未読の投稿がありますよ」イベントを発行する
 	setTimeout(async () => {
-		const exist = await NoteUnreads.findOneBy({ id: unread.id });
+		const exist = await NoteUnreads.exist({ where: { id: unread.id } });
 
-		if (exist == null) return;
+		if (!exist) return;
 
 		if (params.isMentioned) {
 			publishMainStream(userId, "unreadMention", note.id);