diff --git a/src/modules/mileage/MonitoringView.tsx b/src/modules/mileage/MonitoringView.tsx
index d0886bb..0638ab8 100644
--- a/src/modules/mileage/MonitoringView.tsx
+++ b/src/modules/mileage/MonitoringView.tsx
@@ -104,7 +104,11 @@ export default function MonitoringView() {
   const [filterRegionCode, setFilterRegionCode] = useState('All');
   const [filterMileageRange, setFilterMileageRange] = useState({ min: '', max: '' });
   const [appliedMileageRange, setAppliedMileageRange] = useState({ min: '', max: '' });
-  const [filterDate, setFilterDate] = useState(() => new Date().toISOString().split('T')[0]);
+  const [filterDate, setFilterDate] = useState(() => {
+    const now = new Date();
+    if (now.getHours() < 5) now.setDate(now.getDate() - 1);
+    return `${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, '0')}-${String(now.getDate()).padStart(2, '0')}`;
+  });
 
   const [vehicles, setVehicles] = useState<MonitoringVehicle[]>([]);
   const [stats, setStats] = useState<MonitoringStats>({ totalToday: 0, totalAll: 0, vehicleCount: 0, yesterdayTotal: 0 });