diff --git a/packages/backend/src/core/activitypub/ApDbResolverService.ts b/packages/backend/src/core/activitypub/ApDbResolverService.ts
index 79a8fcc5d1..97cd5e3701 100644
--- a/packages/backend/src/core/activitypub/ApDbResolverService.ts
+++ b/packages/backend/src/core/activitypub/ApDbResolverService.ts
@@ -230,7 +230,7 @@ export class ApDbResolverService implements OnApplicationShutdown {
 		 * keyIdで見つからない場合、まずはキャッシュを更新して再取得
 		 * If not found with keyId, update cache and reacquire
 		 */
-		const cacheRaw = this.publicKeyByUserIdCache.cache.get(user.id);
+		const cacheRaw = this.publicKeyByUserIdCache.getRaw(user.id);
 		if (cacheRaw && Date.now() - cacheRaw.date > 1000 * 60 * 5) {
 			const exactKey = await this.refreshAndFindKey(user.id, keyId);
 			if (exactKey) return { user, key: exactKey };
diff --git a/packages/backend/src/misc/cache.ts b/packages/backend/src/misc/cache.ts
index 4fa3693995..42a00654ef 100644
--- a/packages/backend/src/misc/cache.ts
+++ b/packages/backend/src/misc/cache.ts
@@ -168,11 +168,6 @@ export class RedisSingleCache<T> {
 		return value;
 	}
 
-	@bindThis
-	public getRaw(): T | undefined {
-		return this.memoryCache.get();
-	}
-
 	@bindThis
 	public async delete(): Promise<void> {
 		this.memoryCache.delete();
@@ -242,6 +237,11 @@ export class MemoryKVCache<T> {
 		return cached.value;
 	}
 
+	@bindThis
+	public getRaw(key: string): { date: number; value: T; } | undefined {
+		return this.cache.get(key);
+	}
+
 	@bindThis
 	public delete(key: string): void {
 		this.cache.delete(key);