diff --git a/packages/backend/src/core/CustomEmojiService.ts b/packages/backend/src/core/CustomEmojiService.ts
index 078351327f..cb23a2f8c0 100644
--- a/packages/backend/src/core/CustomEmojiService.ts
+++ b/packages/backend/src/core/CustomEmojiService.ts
@@ -115,20 +115,20 @@ export class CustomEmojiService implements OnApplicationShutdown {
 		roleIdsThatCanBeUsedThisEmojiAsReaction?: MiRole['id'][];
 	}, moderator?: MiUser): Promise<
 		void
-		| "NO_SUCH_EMOJI"
-		| "SAME_NAME_EMOJI_EXISTS"
+		| 'NO_SUCH_EMOJI'
+		| 'SAME_NAME_EMOJI_EXISTS'
 	> {
 		const emoji = data.id
 			? await this.getEmojiById(data.id)
 			: await this.getEmojiByName(data.name!);
-		if (emoji === null) return "NO_SUCH_EMOJI";
+		if (emoji === null) return 'NO_SUCH_EMOJI';
 		const id = emoji.id;
 
 		// IDと絵文字名が両方指定されている場合は絵文字名の変更を行うため重複チェックが必要
 		const doNameUpdate = data.id && data.name && (data.name !== emoji.name);
 		if (doNameUpdate) {
 			const isDuplicate = await this.checkDuplicate(data.name!);
-			if (isDuplicate) return "SAME_NAME_EMOJI_EXISTS";
+			if (isDuplicate) return 'SAME_NAME_EMOJI_EXISTS';
 		}
 
 		await this.emojisRepository.update(emoji.id, {
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/update.ts b/packages/backend/src/server/api/endpoints/admin/emoji/update.ts
index 2e6a662be2..95ee1d0810 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/update.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/update.ts
@@ -96,8 +96,8 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 
 			switch (error) {
 				case undefined: return;
-				case "NO_SUCH_EMOJI": throw new ApiError(meta.errors.noSuchEmoji);
-				case "SAME_NAME_EMOJI_EXISTS": throw new ApiError(meta.errors.sameNameEmojiExists);
+				case 'NO_SUCH_EMOJI': throw new ApiError(meta.errors.noSuchEmoji);
+				case 'SAME_NAME_EMOJI_EXISTS': throw new ApiError(meta.errors.sameNameEmojiExists);
 			}
 		});
 	}