diff --git a/src/public/upload.css b/src/public/upload.css
index a53bc92..4dc568c 100644
--- a/src/public/upload.css
+++ b/src/public/upload.css
@@ -233,6 +233,14 @@ h1 {
   outline-offset: 2px;
 }
 
+.guest-fields__anonymous {
+  color: #a64635;
+  font-family: "Apple SD Gothic Neo", "Malgun Gothic", system-ui, sans-serif;
+  font-size: 13px;
+  font-weight: 700;
+  line-height: 1.45;
+}
+
 .file-picker input[type="file"] {
   position: absolute;
   inset: 0;
diff --git a/src/public/upload.html b/src/public/upload.html
index 2867866..66376f6 100644
--- a/src/public/upload.html
+++ b/src/public/upload.html
@@ -15,12 +15,13 @@
 
       <form class="upload-panel" method="post" action="/r/{{slug}}" enctype="multipart/form-data">
         <p class="upload-panel__today">오늘의 순간</p>
-        <p class="upload-panel__notice">※ 연락처는 상품 전달 목적 외에는 사용되지 않으며, 전달 후 삭제됩니다.<br>※ 익명 제출 시 경품 대상에서 제외됩니다.</p>
+        <p class="upload-panel__notice">※ 연락처는 상품 전달 목적 외에는 사용되지 않으며, 전달 후 삭제됩니다.</p>
 
         <div class="guest-fields" aria-label="업로드하시는 분 정보">
           <label>
             <span>연락처</span>
             <input type="tel" name="guestPhone" autocomplete="tel" inputmode="tel" value="010-">
+            <span class="guest-fields__anonymous" hidden>※ 익명 제출 시 추첨 대상에서 제외됩니다.</span>
           </label>
         </div>
 
@@ -54,6 +55,8 @@
   <script>
     document.querySelectorAll(".upload-panel").forEach((form) => {
       const input = form.querySelector('input[type="file"][name="files"]');
+      const guestPhone = form.querySelector('input[name="guestPhone"]');
+      const anonymousNotice = form.querySelector(".guest-fields__anonymous");
       const submit = form.querySelector('button[type="submit"][aria-label="업로드"]');
       const summary = form.querySelector(".file-summary");
       const empty = form.querySelector(".file-summary__empty");
@@ -86,6 +89,14 @@
         scrollTopButton.hidden = list.scrollHeight <= list.clientHeight || list.scrollTop < 8;
       };
 
+      const hasValidPhone = () => /^010\d{8}$/.test((guestPhone?.value || "").replace(/\D/g, ""));
+
+      const updateAnonymousNotice = () => {
+        if (!anonymousNotice) return;
+        const hasFiles = Boolean(input?.files && input.files.length > 0);
+        anonymousNotice.hidden = !hasFiles || hasValidPhone();
+      };
+
       input?.addEventListener("change", () => {
         const files = Array.from(input.files || []);
         clearPreviews();
@@ -98,6 +109,7 @@
           submit.disabled = true;
           submit.hidden = true;
           updateScrollTopButton();
+          updateAnonymousNotice();
           setStatus("");
           return;
         }
@@ -135,9 +147,12 @@
         submit.hidden = false;
         list.scrollTop = 0;
         requestAnimationFrame(updateScrollTopButton);
+        updateAnonymousNotice();
         setStatus(`${files.length}개 파일을 선택했어요.`);
       });
 
+      guestPhone?.addEventListener("input", updateAnonymousNotice);
+
       list.addEventListener("scroll", updateScrollTopButton);
       scrollTopButton?.addEventListener("click", () => {
         list.scrollTo({ top: 0, behavior: "smooth" });
diff --git a/src/server.js b/src/server.js
index c145ee7..d7a3556 100644
--- a/src/server.js
+++ b/src/server.js
@@ -66,7 +66,7 @@ function cleanGuestField(value) {
 
 function submissionFolderName(guestPhone) {
   const phone = cleanGuestField(guestPhone).replace(/[^\d]/g, "");
-  return phone || "익명";
+  return /^010\d{8}$/.test(phone) ? phone : "익명";
 }
 
 function normalizeExts(value) {