diff --git a/packages/backend/src/models/entities/user.ts b/packages/backend/src/models/entities/user.ts
index 1be1909ec..b07e22929 100644
--- a/packages/backend/src/models/entities/user.ts
+++ b/packages/backend/src/models/entities/user.ts
@@ -262,3 +262,5 @@ export type CacheableRemoteUser = {
 	featured: IRemoteUser['featured'];
 	followersUri: IRemoteUser['followersUri'];
 };
+
+export type CacheableUser = CacheableLocalUser | CacheableRemoteUser;
diff --git a/packages/backend/src/remote/activitypub/audience.ts b/packages/backend/src/remote/activitypub/audience.ts
index b47e9e994..846ccf9c0 100644
--- a/packages/backend/src/remote/activitypub/audience.ts
+++ b/packages/backend/src/remote/activitypub/audience.ts
@@ -3,14 +3,14 @@ import Resolver from './resolver.js';
 import { resolvePerson } from './models/person.js';
 import { unique, concat } from '@/prelude/array.js';
 import promiseLimit from 'promise-limit';
-import { User, CacheableRemoteUser } from '@/models/entities/user.js';
+import { User, CacheableRemoteUser, CacheableUser } from '@/models/entities/user.js';
 
 type Visibility = 'public' | 'home' | 'followers' | 'specified';
 
 type AudienceInfo = {
 	visibility: Visibility,
-	mentionedUsers: User[],
-	visibleUsers: User[],
+	mentionedUsers: CacheableUser[],
+	visibleUsers: CacheableUser[],
 };
 
 export async function parseAudience(actor: CacheableRemoteUser, to?: ApObject, cc?: ApObject, resolver?: Resolver): Promise<AudienceInfo> {
@@ -19,10 +19,10 @@ export async function parseAudience(actor: CacheableRemoteUser, to?: ApObject, c
 
 	const others = unique(concat([toGroups.other, ccGroups.other]));
 
-	const limit = promiseLimit<User | null>(2);
+	const limit = promiseLimit<CacheableUser | null>(2);
 	const mentionedUsers = (await Promise.all(
 		others.map(id => limit(() => resolvePerson(id, resolver).catch(() => null)))
-	)).filter((x): x is User => x != null);
+	)).filter((x): x is CacheableUser => x != null);
 
 	if (toGroups.public.length > 0) {
 		return {
diff --git a/packages/backend/src/remote/activitypub/db-resolver.ts b/packages/backend/src/remote/activitypub/db-resolver.ts
index 20c96af8f..5c748bd61 100644
--- a/packages/backend/src/remote/activitypub/db-resolver.ts
+++ b/packages/backend/src/remote/activitypub/db-resolver.ts
@@ -109,10 +109,11 @@ export default class DbResolver {
 		user: CacheableRemoteUser;
 		key?: UserPublickey;
 	} | null> {
-		const user = await resolvePerson(uri) as IRemoteUser;
+		const user = await resolvePerson(uri) as CacheableRemoteUser;
 
 		if (user == null) return null;
 
+		// TODO: cache
 		const key = await UserPublickeys.findOne(user.id);
 
 		return {
diff --git a/packages/backend/src/remote/activitypub/models/image.ts b/packages/backend/src/remote/activitypub/models/image.ts
index b5e9181d3..1bdb769a6 100644
--- a/packages/backend/src/remote/activitypub/models/image.ts
+++ b/packages/backend/src/remote/activitypub/models/image.ts
@@ -1,10 +1,10 @@
 import { uploadFromUrl } from '@/services/drive/upload-from-url.js';
-import { IRemoteUser } from '@/models/entities/user.js';
+import { CacheableRemoteUser, IRemoteUser } from '@/models/entities/user.js';
 import Resolver from '../resolver.js';
 import { fetchMeta } from '@/misc/fetch-meta.js';
 import { apLogger } from '../logger.js';
 import { DriveFile } from '@/models/entities/drive-file.js';
-import { DriveFiles } from '@/models/index.js';
+import { DriveFiles, Users } from '@/models/index.js';
 import { truncate } from '@/misc/truncate.js';
 import { DB_MAX_IMAGE_COMMENT_LENGTH } from '@/misc/hard-limits.js';
 
@@ -13,9 +13,9 @@ const logger = apLogger;
 /**
  * Imageを作成します。
  */
-export async function createImage(actor: IRemoteUser, value: any): Promise<DriveFile> {
+export async function createImage(actor: CacheableRemoteUser, value: any): Promise<DriveFile> {
 	// 投稿者が凍結されていたらスキップ
-	if (actor.isSuspended) {
+	if (Users.checkSuspended(actor.id)) {
 		throw new Error('actor has been suspended');
 	}
 
@@ -60,7 +60,7 @@ export async function createImage(actor: IRemoteUser, value: any): Promise<Drive
  * Misskeyに対象のImageが登録されていればそれを返し、そうでなければ
  * リモートサーバーからフェッチしてMisskeyに登録しそれを返します。
  */
-export async function resolveImage(actor: IRemoteUser, value: any): Promise<DriveFile> {
+export async function resolveImage(actor: CacheableRemoteUser, value: any): Promise<DriveFile> {
 	// TODO
 
 	// リモートサーバーからフェッチしてきて登録
diff --git a/packages/backend/src/remote/activitypub/models/mention.ts b/packages/backend/src/remote/activitypub/models/mention.ts
index c5b0ea53c..a16009296 100644
--- a/packages/backend/src/remote/activitypub/models/mention.ts
+++ b/packages/backend/src/remote/activitypub/models/mention.ts
@@ -3,17 +3,17 @@ import { IObject, isMention, IApMention } from '../type.js';
 import { resolvePerson } from './person.js';
 import promiseLimit from 'promise-limit';
 import Resolver from '../resolver.js';
-import { User } from '@/models/entities/user.js';
+import { CacheableUser, User } from '@/models/entities/user.js';
 
 export async function extractApMentions(tags: IObject | IObject[] | null | undefined) {
 	const hrefs = unique(extractApMentionObjects(tags).map(x => x.href as string));
 
 	const resolver = new Resolver();
 
-	const limit = promiseLimit<User | null>(2);
+	const limit = promiseLimit<CacheableUser | null>(2);
 	const mentionedUsers = (await Promise.all(
 		hrefs.map(x => limit(() => resolvePerson(x, resolver).catch(() => null)))
-	)).filter((x): x is User => x != null);
+	)).filter((x): x is CacheableUser => x != null);
 
 	return mentionedUsers;
 }
diff --git a/packages/backend/src/remote/activitypub/models/note.ts b/packages/backend/src/remote/activitypub/models/note.ts
index dca64d0a6..4dcc9d194 100644
--- a/packages/backend/src/remote/activitypub/models/note.ts
+++ b/packages/backend/src/remote/activitypub/models/note.ts
@@ -5,7 +5,7 @@ import Resolver from '../resolver.js';
 import post from '@/services/note/create.js';
 import { resolvePerson, updatePerson } from './person.js';
 import { resolveImage } from './image.js';
-import { IRemoteUser } from '@/models/entities/user.js';
+import { CacheableRemoteUser, IRemoteUser } from '@/models/entities/user.js';
 import { htmlToMfm } from '../misc/html-to-mfm.js';
 import { extractApHashtags } from './tag.js';
 import { unique, toArray, toSingle } from '@/prelude/array.js';
@@ -15,7 +15,7 @@ import { apLogger } from '../logger.js';
 import { DriveFile } from '@/models/entities/drive-file.js';
 import { deliverQuestionUpdate } from '@/services/note/polls/update.js';
 import { extractDbHost, toPuny } from '@/misc/convert-host.js';
-import { Emojis, Polls, MessagingMessages } from '@/models/index.js';
+import { Emojis, Polls, MessagingMessages, Users } from '@/models/index.js';
 import { Note } from '@/models/entities/note.js';
 import { IObject, getOneApId, getApId, getOneApHrefNullable, validPost, IPost, isEmoji, getApType } from '../type.js';
 import { Emoji } from '@/models/entities/emoji.js';
@@ -90,10 +90,10 @@ export async function createNote(value: string | IObject, resolver?: Resolver, s
 	logger.info(`Creating the Note: ${note.id}`);
 
 	// 投稿者をフェッチ
-	const actor = await resolvePerson(getOneApId(note.attributedTo), resolver) as IRemoteUser;
+	const actor = await resolvePerson(getOneApId(note.attributedTo), resolver) as CacheableRemoteUser;
 
 	// 投稿者が凍結されていたらスキップ
-	if (actor.isSuspended) {
+	if (Users.checkSuspended(actor.id)) {
 		throw new Error('actor has been suspended');
 	}
 
@@ -230,11 +230,6 @@ export async function createNote(value: string | IObject, resolver?: Resolver, s
 
 	const poll = await extractPollFromQuestion(note, resolver).catch(() => undefined);
 
-	// ユーザーの情報が古かったらついでに更新しておく
-	if (actor.lastFetchedAt == null || Date.now() - actor.lastFetchedAt.getTime() > 1000 * 60 * 60 * 24) {
-		if (actor.uri) updatePerson(actor.uri);
-	}
-
 	if (isTalk) {
 		for (const recipient of visibleUsers) {
 			await createMessage(actor, recipient, undefined, text || undefined, (files && files.length > 0) ? files[0] : null, object.id);
diff --git a/packages/backend/src/remote/activitypub/models/person.ts b/packages/backend/src/remote/activitypub/models/person.ts
index 70d6a1072..9ea879705 100644
--- a/packages/backend/src/remote/activitypub/models/person.ts
+++ b/packages/backend/src/remote/activitypub/models/person.ts
@@ -15,7 +15,7 @@ import { apLogger } from '../logger.js';
 import { Note } from '@/models/entities/note.js';
 import { updateUsertags } from '@/services/update-hashtag.js';
 import { Users, Instances, DriveFiles, Followings, UserProfiles, UserPublickeys } from '@/models/index.js';
-import { User, IRemoteUser } from '@/models/entities/user.js';
+import { User, IRemoteUser, CacheableUser } from '@/models/entities/user.js';
 import { Emoji } from '@/models/entities/emoji.js';
 import { UserNotePining } from '@/models/entities/user-note-pining.js';
 import { genId } from '@/misc/gen-id.js';
@@ -32,7 +32,7 @@ import { truncate } from '@/misc/truncate.js';
 import { StatusError } from '@/misc/fetch.js';
 import { Cache } from '@/misc/cache.js';
 
-const uriPersonCache = new Cache<User | null>(Infinity);
+const uriPersonCache = new Cache<CacheableUser | null>(Infinity);
 
 const logger = apLogger;
 
@@ -93,22 +93,26 @@ function validateActor(x: IObject, uri: string): IActor {
  * Personをフェッチします。
  *
  * Misskeyに対象のPersonが登録されていればそれを返します。
- * 
- * TODO: cache
  */
-export async function fetchPerson(uri: string, resolver?: Resolver): Promise<User | null> {
+export async function fetchPerson(uri: string, resolver?: Resolver): Promise<CacheableUser | null> {
 	if (typeof uri !== 'string') throw new Error('uri is not string');
 
+	const cached = uriPersonCache.get(uri);
+	if (cached) return cached;
+
 	// URIがこのサーバーを指しているならデータベースからフェッチ
 	if (uri.startsWith(config.url + '/')) {
 		const id = uri.split('/').pop();
-		return await Users.findOne(id).then(x => x || null);
+		const u = await Users.findOne(id).then(x => x || null); // TODO: typeorm 3.0 にしたら .then(x => x || null) を消す
+		if (u) uriPersonCache.set(uri, u);
+		return u;
 	}
 
 	//#region このサーバーに既に登録されていたらそれを返す
 	const exist = await Users.findOne({ uri });
 
 	if (exist) {
+		uriPersonCache.set(uri, exist);
 		return exist;
 	}
 	//#endregion
@@ -376,7 +380,7 @@ export async function updatePerson(uri: string, resolver?: Resolver | null, hint
  * Misskeyに対象のPersonが登録されていればそれを返し、そうでなければ
  * リモートサーバーからフェッチしてMisskeyに登録しそれを返します。
  */
-export async function resolvePerson(uri: string, resolver?: Resolver): Promise<User> {
+export async function resolvePerson(uri: string, resolver?: Resolver): Promise<CacheableUser> {
 	if (typeof uri !== 'string') throw new Error('uri is not string');
 
 	//#region このサーバーに既に登録されていたらそれを返す
diff --git a/packages/backend/src/services/messages/create.ts b/packages/backend/src/services/messages/create.ts
index c3908b255..17479a85f 100644
--- a/packages/backend/src/services/messages/create.ts
+++ b/packages/backend/src/services/messages/create.ts
@@ -1,4 +1,4 @@
-import { User } from '@/models/entities/user.js';
+import { CacheableUser, User } from '@/models/entities/user.js';
 import { UserGroup } from '@/models/entities/user-group.js';
 import { DriveFile } from '@/models/entities/drive-file.js';
 import { MessagingMessages, UserGroupJoinings, Mutings, Users } from '@/models/index.js';
@@ -13,7 +13,7 @@ import renderCreate from '@/remote/activitypub/renderer/create.js';
 import { renderActivity } from '@/remote/activitypub/renderer/index.js';
 import { deliver } from '@/queue/index.js';
 
-export async function createMessage(user: { id: User['id']; host: User['host']; }, recipientUser: User | undefined, recipientGroup: UserGroup | undefined, text: string | null | undefined, file: DriveFile | null, uri?: string) {
+export async function createMessage(user: { id: User['id']; host: User['host']; }, recipientUser: CacheableUser | undefined, recipientGroup: UserGroup | undefined, text: string | null | undefined, file: DriveFile | null, uri?: string) {
 	const message = {
 		id: genId(),
 		createdAt: new Date(),
diff --git a/packages/backend/src/services/note/polls/vote.ts b/packages/backend/src/services/note/polls/vote.ts
index 9b83b1953..c758e3857 100644
--- a/packages/backend/src/services/note/polls/vote.ts
+++ b/packages/backend/src/services/note/polls/vote.ts
@@ -1,12 +1,12 @@
 import { publishNoteStream } from '@/services/stream.js';
-import { User } from '@/models/entities/user.js';
+import { CacheableUser, User } from '@/models/entities/user.js';
 import { Note } from '@/models/entities/note.js';
 import { PollVotes, NoteWatchings, Polls, Blockings } from '@/models/index.js';
 import { Not } from 'typeorm';
 import { genId } from '@/misc/gen-id.js';
 import { createNotification } from '../../create-notification.js';
 
-export default async function(user: User, note: Note, choice: number) {
+export default async function(user: CacheableUser, note: Note, choice: number) {
 	const poll = await Polls.findOne(note.id);
 
 	if (poll == null) throw new Error('poll not found');