diff --git a/backend/templates/admin_members.html b/backend/templates/admin_members.html
index d9b650d..620cf0d 100644
--- a/backend/templates/admin_members.html
+++ b/backend/templates/admin_members.html
@@ -829,15 +829,24 @@
 
     function viewDetail(idx) {
         currentDetailMember = membersData[idx];
-        const phone = currentDetailMember.phone.replace(/-/g, '').replace(/ /g, '');
+        const phone = (currentDetailMember.phone || '').replace(/-/g, '').replace(/ /g, '');
         
         // 모달 열기
         document.getElementById('detailModal').classList.add('active');
         document.getElementById('detailName').textContent = currentDetailMember.name || '이름 없음';
-        document.getElementById('detailPhone').textContent = formatPhone(currentDetailMember.phone);
+        document.getElementById('detailPhone').textContent = formatPhone(currentDetailMember.phone) || '전화번호 없음';
         document.getElementById('detailBalance').textContent = '로딩...';
         document.getElementById('detailContent').innerHTML = '<div class="detail-loading">데이터를 불러오는 중...</div>';
         
+        // 전화번호 없으면 바로 안내
+        if (!phone) {
+            document.getElementById('detailBalance').textContent = '-';
+            document.getElementById('detailContent').innerHTML = 
+                '<div class="detail-empty">📵 전화번호가 등록되지 않은 회원입니다<br><small style="color:#94a3b8;">POS에 전화번호를 등록하면 조회 가능합니다</small></div>';
+            detailData = { mileage: null, purchases: [], prescriptions: [], interests: [] };
+            return;
+        }
+        
         // 데이터 로드
         fetch(`/api/members/history/${phone}`)
             .then(res => res.json())