diff --git a/src/pages/agent-office/components/ActivityItem.jsx b/src/pages/agent-office/components/ActivityItem.jsx
new file mode 100644
index 0000000..9d74252
--- /dev/null
+++ b/src/pages/agent-office/components/ActivityItem.jsx
@@ -0,0 +1,60 @@
+// src/pages/agent-office/components/ActivityItem.jsx
+import { AGENT_META } from '../constants.js';
+
+const STATUS_STYLE = {
+  succeeded: { bg: '#065f46', fg: '#34d399', label: '✓ 완료' },
+  failed:    { bg: '#7f1d1d', fg: '#fca5a5', label: '✗ 실패' },
+  working:   { bg: '#1e3a5f', fg: '#60a5fa', label: '⏳ 진행' },
+  pending:   { bg: '#92400e', fg: '#fbbf24', label: '⏳ 대기' },
+};
+
+const LEVEL_STYLE = {
+  error:   { icon: '❌', cls: 'level-error' },
+  warning: { icon: '⚠️', cls: 'level-warning' },
+  info:    { icon: '·',  cls: 'level-info' },
+};
+
+function formatTime(ts) {
+  if (!ts) return '';
+  const d = new Date(ts);
+  const now = new Date();
+  const isToday = d.toDateString() === now.toDateString();
+  const time = d.toLocaleTimeString('ko-KR', { hour: '2-digit', minute: '2-digit' });
+  return isToday ? time : `${d.getMonth() + 1}/${d.getDate()} ${time}`;
+}
+
+export default function ActivityItem({ item, onSelectAgent }) {
+  const meta = AGENT_META[item.agent_id];
+  const color = meta?.color || '#6b7280';
+  const name = meta?.displayName || item.agent_id;
+  const isTask = item.type === 'task';
+  const status = STATUS_STYLE[item.status] || STATUS_STYLE.pending;
+  const level = LEVEL_STYLE[item.level] || LEVEL_STYLE.info;
+  const highlight = isTask && (item.status === 'pending' || item.status === 'working');
+
+  return (
+    <div
+      className={`ao-activity-item ${isTask ? 'is-task' : 'is-log'} ${highlight ? 'is-highlight' : ''}`}
+      onClick={() => onSelectAgent(item.agent_id)}
+      role="button"
+      tabIndex={0}
+    >
+      <span className="ao-activity-dot" style={{ background: color }} aria-hidden="true" />
+      <div className="ao-activity-body">
+        <div className="ao-activity-line">
+          <span className="ao-activity-agent" style={{ color }}>{name}</span>
+          {isTask
+            ? <span className="ao-activity-badge" style={{ background: status.bg, color: status.fg }}>{status.label}</span>
+            : <span className={`ao-activity-level ${level.cls}`}>{level.icon}</span>}
+        </div>
+        <div className="ao-activity-msg">{item.message}</div>
+      </div>
+      <div className="ao-activity-meta">
+        <span className="ao-activity-time">{formatTime(item.created_at)}</span>
+        {isTask && item.duration_seconds != null && (
+          <span className="ao-activity-dur">{item.duration_seconds}s</span>
+        )}
+      </div>
+    </div>
+  );
+}
diff --git a/src/pages/agent-office/components/ActivityItem.test.jsx b/src/pages/agent-office/components/ActivityItem.test.jsx
new file mode 100644
index 0000000..48f495b
--- /dev/null
+++ b/src/pages/agent-office/components/ActivityItem.test.jsx
@@ -0,0 +1,30 @@
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen, fireEvent } from '@testing-library/react';
+import ActivityItem from './ActivityItem.jsx';
+
+describe('ActivityItem', () => {
+  it('task 항목은 상태 뱃지와 duration을 렌더한다', () => {
+    render(<ActivityItem item={{ type: 'task', agent_id: 'stock', task_id: 'a', message: 'holdings_brief', created_at: '2026-06-10T23:30:00Z', status: 'succeeded', duration_seconds: 2 }} onSelectAgent={() => {}} />);
+    expect(screen.getByText('holdings_brief')).toBeInTheDocument();
+    expect(screen.getByText(/완료/)).toBeInTheDocument();
+    expect(screen.getByText('2s')).toBeInTheDocument();
+  });
+
+  it('log 항목은 level 아이콘을 렌더한다', () => {
+    render(<ActivityItem item={{ type: 'log', agent_id: 'lotto', task_id: 'b', message: 'signal_check', created_at: '2026-06-10T23:15:00Z', level: 'error' }} onSelectAgent={() => {}} />);
+    expect(screen.getByText('signal_check')).toBeInTheDocument();
+    expect(screen.getByText('❌')).toBeInTheDocument();
+  });
+
+  it('클릭 시 onSelectAgent(agent_id)를 호출한다', () => {
+    const onSelect = vi.fn();
+    render(<ActivityItem item={{ type: 'task', agent_id: 'insta', task_id: 'c', message: '발급', created_at: '2026-06-10T23:00:00Z', status: 'pending' }} onSelectAgent={onSelect} />);
+    fireEvent.click(screen.getByText('발급').closest('.ao-activity-item'));
+    expect(onSelect).toHaveBeenCalledWith('insta');
+  });
+
+  it('미지정 agent_id는 id를 그대로 표시한다', () => {
+    render(<ActivityItem item={{ type: 'log', agent_id: 'unknown', task_id: 'd', message: 'x', created_at: '2026-06-10T23:00:00Z', level: 'info' }} onSelectAgent={() => {}} />);
+    expect(screen.getByText('unknown')).toBeInTheDocument();
+  });
+});