diff --git a/routes/api/task.ts b/routes/api/task.ts
index 0d14a13..33ec08c 100644
--- a/routes/api/task.ts
+++ b/routes/api/task.ts
@@ -10,7 +10,9 @@ export const handler: Handlers<Task[]> = {
     GET(req, _ctx) {
         const t = get_task_manager();
         const { socket, response } = Deno.upgradeWebSocket(req);
-        const handle = (e: CustomEvent<Task | TaskProgress>) => {
+        const handle = (
+            e: CustomEvent<Task | TaskProgress | { task: Task; error: string }>,
+        ) => {
             socket.send(JSON.stringify({ type: e.type, detail: e.detail }));
         };
         const removeListener = () => {
@@ -18,6 +20,7 @@ export const handler: Handlers<Task[]> = {
             t.removeEventListener("task_started", handle);
             t.removeEventListener("task_finished", handle);
             t.removeEventListener("task_progress", handle);
+            t.removeEventListener("task_error", handle);
         };
         function sendMessage(mes: TaskServerSocketData) {
             socket.send(JSON.stringify(mes));
@@ -57,6 +60,7 @@ export const handler: Handlers<Task[]> = {
             t.addEventListener("task_started", handle);
             t.addEventListener("task_finished", handle);
             t.addEventListener("task_progress", handle);
+            t.addEventListener("task_error", handle);
         };
         return response;
     },
diff --git a/task.ts b/task.ts
index 820fec4..f9d04a5 100644
--- a/task.ts
+++ b/task.ts
@@ -14,6 +14,7 @@ export type Task<T extends TaskType = TaskType> = {
 
 export type TaskDownloadProgess = {
     downloaded_page: number;
+    failed_page: number;
     total_page: number;
 };
 
diff --git a/task_manager.ts b/task_manager.ts
index 2f50556..91746fc 100644
--- a/task_manager.ts
+++ b/task_manager.ts
@@ -25,6 +25,7 @@ type EventMap = {
     task_started: Task;
     task_finished: Task;
     task_progress: TaskProgress;
+    task_error: { task: Task; error: string };
 };
 
 type Detail<T extends Record<PropertyKey, unknown>> = {
@@ -142,7 +143,13 @@ export class TaskManager extends EventTarget {
                 await this.db.delete_task(status.value);
                 this.dispatchEvent("task_finished", status.value);
             } else if (status.status == PromiseStatus.Rejected) {
-                if (status.reason && !this.aborted) console.log(status.reason);
+                if (status.reason && !this.aborted) {
+                    console.log(status.reason);
+                    this.dispatchEvent("task_error", {
+                        task: task.base,
+                        error: status.reason.toString(),
+                    });
+                }
                 removed_task.push(id);
             }
         }
diff --git a/tasks/download.ts b/tasks/download.ts
index 23d78e5..d88bbb9 100644
--- a/tasks/download.ts
+++ b/tasks/download.ts
@@ -20,7 +20,6 @@ class DownloadManager {
     #force_abort: AbortSignal;
     #max_download_count;
     #running_tasks: Promise<unknown>[];
-    #has_failed_task = false;
     #progress: TaskDownloadProgess;
     #task: Task;
     #manager: TaskManager;
@@ -35,7 +34,7 @@ class DownloadManager {
         this.#running_tasks = [];
         this.#abort = abort;
         this.#force_abort = force_abort;
-        this.#progress = { total_page: 0, downloaded_page: 0 };
+        this.#progress = { downloaded_page: 0, failed_page: 0, total_page: 0 };
         this.#task = task;
         this.#manager = manager;
     }
@@ -46,7 +45,8 @@ class DownloadManager {
                 const s = await promiseState(t);
                 if (s.status === PromiseStatus.Rejected) {
                     if (!this.#force_abort.aborted) console.log(s.reason);
-                    this.#has_failed_task = true;
+                    this.#progress.failed_page += 1;
+                    this.#sendEvent();
                 } else if (s.status === PromiseStatus.Fulfilled) {
                     this.#progress.downloaded_page += 1;
                     this.#sendEvent();
@@ -59,10 +59,7 @@ class DownloadManager {
         return this.#manager.dispatchTaskProgressEvent(
             TaskType.Download,
             this.#task.id,
-            {
-                downloaded_page: this.#progress.downloaded_page,
-                total_page: this.#progress.total_page,
-            },
+            this.#progress,
         );
     }
     async add_new_task(f: () => Promise<unknown>) {
@@ -77,7 +74,7 @@ class DownloadManager {
         }
     }
     get has_failed_task() {
-        return this.#has_failed_task;
+        return this.#progress.failed_page > 0;
     }
     async join() {
         while (1) {