diff --git a/src/queue/processors/inbox.ts b/src/queue/processors/inbox.ts
index 481bcbb1c..35b0ce538 100644
--- a/src/queue/processors/inbox.ts
+++ b/src/queue/processors/inbox.ts
@@ -13,6 +13,7 @@ import { instanceChart } from '../../services/chart';
 import { UserPublickey } from '../../models/entities/user-publickey';
 import fetchMeta from '../../misc/fetch-meta';
 import { toPuny } from '../../misc/convert-host';
+import { validActor } from '../../remote/activitypub/type';
 
 const logger = new Logger('inbox');
 
@@ -93,7 +94,7 @@ export default async (job: Bull.Job): Promise<void> => {
 
 	// Update Person activityの場合は、ここで署名検証/更新処理まで実施して終了
 	if (activity.type === 'Update') {
-		if (activity.object && activity.object.type === 'Person') {
+		if (activity.object && validActor.includes(activity.object.type)) {
 			if (user == null) {
 				logger.warn('Update activity received, but user not registed.');
 			} else if (!httpSignature.verifySignature(signature, key.keyPem)) {
diff --git a/src/remote/activitypub/models/person.ts b/src/remote/activitypub/models/person.ts
index e13ef21eb..b2edf3973 100644
--- a/src/remote/activitypub/models/person.ts
+++ b/src/remote/activitypub/models/person.ts
@@ -24,6 +24,7 @@ import { UserPublickey } from '../../../models/entities/user-publickey';
 import { isDuplicateKeyValueError } from '../../../misc/is-duplicate-key-value-error';
 import { toPuny } from '../../../misc/convert-host';
 import { UserProfile } from '../../../models/entities/user-profile';
+import { validActor } from '../../../remote/activitypub/type';
 const logger = apLogger;
 
 /**
@@ -38,7 +39,7 @@ function validatePerson(x: any, uri: string) {
 		return new Error('invalid person: object is null');
 	}
 
-	if (x.type != 'Person' && x.type != 'Service') {
+	if (!validActor.includes(x.type)) {
 		return new Error(`invalid person: object is not a person or service '${x.type}'`);
 	}
 
diff --git a/src/remote/activitypub/type.ts b/src/remote/activitypub/type.ts
index c381e6350..7e81a7cc4 100644
--- a/src/remote/activitypub/type.ts
+++ b/src/remote/activitypub/type.ts
@@ -65,6 +65,8 @@ interface IQuestionChoice {
 	_misskey_votes?: number;
 }
 
+export const validActor = ['Person', 'Service'];
+
 export interface IPerson extends IObject {
 	type: 'Person';
 	name: string;
diff --git a/src/server/api/endpoints/ap/show.ts b/src/server/api/endpoints/ap/show.ts
index 7378e3edc..35c5dd318 100644
--- a/src/server/api/endpoints/ap/show.ts
+++ b/src/server/api/endpoints/ap/show.ts
@@ -10,6 +10,7 @@ import { Users, Notes } from '../../../../models';
 import { Note } from '../../../../models/entities/note';
 import { User } from '../../../../models/entities/user';
 import fetchMeta from '../../../../misc/fetch-meta';
+import { validActor } from '../../../../remote/activitypub/type';
 
 export const meta = {
 	tags: ['federation'],
@@ -110,7 +111,7 @@ async function fetchAny(uri: string) {
 	}
 
 	// それでもみつからなければ新規であるため登録
-	if (object.type === 'Person') {
+	if (validActor.includes(object.type)) {
 		const user = await createPerson(object.id);
 		return {
 			type: 'User',