diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/add.ts b/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
index 1b9dc1c2ae..faab8ee608 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
@@ -69,8 +69,9 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 		super(meta, paramDef, async (ps, me) => {
 			const driveFile = await this.driveFilesRepository.findOneBy({ id: ps.fileId });
 			if (driveFile == null) throw new ApiError(meta.errors.noSuchFile);
-			const duplicateCheck = await this.customEmojiService.isDuplicateCheck(ps.name);
-			if (duplicateCheck != null) throw new ApiError(meta.errors.duplicateName);
+			const isDuplicate = await this.customEmojiService.checkDuplicate(ps.name);
+			if (isDuplicate) throw new ApiError(meta.errors.duplicateName);
+
 			const emoji = await this.customEmojiService.add({
 				driveFile,
 				name: ps.name,