diff --git a/packages/backend/src/remote/activitypub/renderer/read.ts b/packages/backend/src/remote/activitypub/renderer/read.ts
deleted file mode 100644
index a30e649f6..000000000
--- a/packages/backend/src/remote/activitypub/renderer/read.ts
+++ /dev/null
@@ -1,9 +0,0 @@
-import config from '@/config/index.js';
-import { User } from '@/models/entities/user.js';
-import { MessagingMessage } from '@/models/entities/messaging-message.js';
-
-export const renderReadActivity = (user: { id: User['id'] }, message: MessagingMessage) => ({
-	type: 'Read',
-	actor: `${config.url}/users/${user.id}`,
-	object: message.uri,
-});
diff --git a/packages/backend/src/server/api/common/read-messaging-message.ts b/packages/backend/src/server/api/common/read-messaging-message.ts
index 5f3ea8e27..9f713a9d6 100644
--- a/packages/backend/src/server/api/common/read-messaging-message.ts
+++ b/packages/backend/src/server/api/common/read-messaging-message.ts
@@ -7,10 +7,6 @@ import { MessagingMessages, UserGroupJoinings, Users } from '@/models/index.js';
 import { IdentifiableError } from '@/misc/identifiable-error.js';
 import { UserGroup } from '@/models/entities/user-group.js';
 import { toArray } from '@/prelude/array.js';
-import { renderReadActivity } from '@/remote/activitypub/renderer/read.js';
-import { renderActivity } from '@/remote/activitypub/renderer/index.js';
-import { deliver } from '@/queue/index.js';
-import orderedCollection from '@/remote/activitypub/renderer/ordered-collection.js';
 
 /**
  * Mark messages as read
@@ -133,18 +129,3 @@ export async function readGroupMessagingMessage(
 		}
 	}
 }
-
-export async function deliverReadActivity(user: { id: User['id']; host: null; }, recipient: IRemoteUser, messages: MessagingMessage | MessagingMessage[]) {
-	const contents = toArray(messages)
-		.filter(x => x.uri)
-		.map(x => renderReadActivity(user, x));
-
-	if (contents.length > 1) {
-		const collection = orderedCollection(null, contents.length, undefined, undefined, contents);
-		deliver(renderActivity(collection), recipient.inbox);
-	} else {
-		for (const content of contents) {
-			deliver(renderActivity(content), recipient.inbox);
-		}
-	}
-}
diff --git a/packages/backend/src/server/api/endpoints/messaging/messages.ts b/packages/backend/src/server/api/endpoints/messaging/messages.ts
index f00b84e49..db7184a0b 100644
--- a/packages/backend/src/server/api/endpoints/messaging/messages.ts
+++ b/packages/backend/src/server/api/endpoints/messaging/messages.ts
@@ -4,7 +4,7 @@ import define from '@/server/api/define.js';
 import { ApiError } from '@/server/api/error.js';
 import { getUser } from '@/server/api/common/getters.js';
 import { makePaginationQuery } from '@/server/api/common/make-pagination-query.js';
-import { readUserMessagingMessage, readGroupMessagingMessage, deliverReadActivity } from '@/server/api/common/read-messaging-message.js';
+import { readUserMessagingMessage, readGroupMessagingMessage } from '@/server/api/common/read-messaging-message.js';
 
 export const meta = {
 	tags: ['messaging'],
@@ -75,11 +75,6 @@ export default define(meta, paramDef, async (ps, user) => {
 		// Mark all as read
 		if (ps.markAsRead) {
 			readUserMessagingMessage(user.id, recipient.id, messages.filter(m => m.recipientId === user.id).map(x => x.id));
-
-			// リモートユーザーとのメッセージだったら既読配信
-			if (Users.isLocalUser(user) && Users.isRemoteUser(recipient)) {
-				deliverReadActivity(user, recipient, messages);
-			}
 		}
 
 		return await Promise.all(messages.map(message => MessagingMessages.pack(message, user, {
diff --git a/packages/backend/src/server/api/stream/channels/messaging.ts b/packages/backend/src/server/api/stream/channels/messaging.ts
index e10ede776..009acf440 100644
--- a/packages/backend/src/server/api/stream/channels/messaging.ts
+++ b/packages/backend/src/server/api/stream/channels/messaging.ts
@@ -1,7 +1,7 @@
 import { UserGroupJoinings, Users, MessagingMessages } from '@/models/index.js';
 import { User, ILocalUser, IRemoteUser } from '@/models/entities/user.js';
 import { UserGroup } from '@/models/entities/user-group.js';
-import { readUserMessagingMessage, readGroupMessagingMessage, deliverReadActivity } from '@/server/api/common/read-messaging-message.js';
+import { readUserMessagingMessage, readGroupMessagingMessage } from '@/server/api/common/read-messaging-message.js';
 import Channel from '@/server/api/stream/channel.js';
 import { StreamMessages } from '@/server/api/stream/types.js';
 
@@ -69,13 +69,6 @@ export default class extends Channel {
 			case 'read':
 				if (this.otherpartyId) {
 					readUserMessagingMessage(this.user!.id, this.otherpartyId, [body.id]);
-
-					// リモートユーザーからのメッセージだったら既読配信
-					if (Users.isLocalUser(this.user!) && Users.isRemoteUser(this.otherparty!)) {
-						MessagingMessages.findOneBy({ id: body.id }).then(message => {
-							if (message) deliverReadActivity(this.user as ILocalUser, this.otherparty as IRemoteUser, message);
-						});
-					}
 				} else if (this.groupId) {
 					readGroupMessagingMessage(this.user!.id, this.groupId, [body.id]);
 				}