diff --git a/app/routers/orders.py b/app/routers/orders.py
index 89e54bf..1d932a3 100644
--- a/app/routers/orders.py
+++ b/app/routers/orders.py
@@ -842,10 +842,10 @@ def upload_file(
                 )
         excel_io.seek(0)
 
-        # 6. 다운로드 파일명: "MM월 DD일 (요일)_발주_(낱개 상품 출고).xls"
+        # 6. 다운로드 파일명: "MM월 DD일 (요일)_발주_(낱개 상품 출고).xlsx"
         weekdays = ["월요일", "화요일", "수요일", "목요일", "금요일", "토요일", "일요일"]
         weekday_str = weekdays[order_date_dt.weekday()]
-        filename = f"{order_date_dt.strftime('%m')}월 {order_date_dt.strftime('%d')}일 ({weekday_str})_발주_(낱개 상품 출고).xls"
+        filename = f"{order_date_dt.strftime('%m')}월 {order_date_dt.strftime('%d')}일 ({weekday_str})_발주_(낱개 상품 출고).xlsx"
         encoded_filename = quote(filename)
 
         headers = {
diff --git a/static/js/app.js b/static/js/app.js
index 160bc8b..9692a06 100644
--- a/static/js/app.js
+++ b/static/js/app.js
@@ -438,7 +438,7 @@ document.addEventListener('DOMContentLoaded', () => {
             });
             
             if (response.ok) {
-                let downloadFilename = '낱개상품출고.xls';
+                let downloadFilename = '낱개상품출고.xlsx';
                 const disposition = response.headers.get('Content-Disposition');
                 if (disposition && disposition.indexOf('filename*=') !== -1) {
                     const matches = disposition.split("filename*=UTF-8''");