diff --git a/CHANGELOG.md b/CHANGELOG.md
index b355712d94..143b63f7b2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -264,9 +264,6 @@
 - Feat: `/drive/files/create` のリクエストに対応（`multipart/form-data`に対応）
 - Feat: `/admin/role/create` のロールポリシーの型を修正
 
-### Misskey.js
-- Feat: reject時のエラーに型情報を追加
-
 ## 2024.5.0
 
 ### Note
diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index e6687e702f..21cf0f0f01 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -772,13 +772,13 @@ class APIClient {
 }
 
 // @public (undocumented)
-class APIError extends Error {
-    // (undocumented)
-    readonly [MK_API_ERROR] = true;
-    constructor(response: any);
-    // (undocumented)
-    payload: any;
-}
+type APIError = {
+    id: string;
+    code: string;
+    message: string;
+    kind: 'client' | 'server';
+    info: Record<string, any>;
+};
 
 // @public (undocumented)
 type App = components['schemas']['App'];
diff --git a/packages/misskey-js/src/api.ts b/packages/misskey-js/src/api.ts
index 69e16dc02b..0b4a075450 100644
--- a/packages/misskey-js/src/api.ts
+++ b/packages/misskey-js/src/api.ts
@@ -9,16 +9,14 @@ export type {
 
 const MK_API_ERROR = Symbol();
 
-export class APIError extends Error {
-
-	public payload;
-	public readonly [MK_API_ERROR] = true;
-
-	constructor(response: any) {
-		super('message' in response ? response.message : 'API Error');
-		this.payload = response;
-	}
-}
+export type APIError = {
+	id: string;
+	code: string;
+	message: string;
+	kind: 'client' | 'server';
+	// eslint-disable-next-line @typescript-eslint/no-explicit-any
+	info: Record<string, any>;
+};
 
 export function isAPIError(reason: any) {
 	return reason instanceof Error && MK_API_ERROR in reason;
@@ -119,7 +117,7 @@ export class APIClient {
 				if (res.status === 200 || res.status === 204) {
 					resolve(body);
 				} else {
-					reject(new APIError(body.error));
+					reject(new Error(body.error));
 				}
 			}).catch((reason) => {
 				reject(new Error(reason));