diff --git a/frontend/src/common/components/map/S57EncOverlay.tsx b/frontend/src/common/components/map/S57EncOverlay.tsx
index 9211754..4384d45 100644
--- a/frontend/src/common/components/map/S57EncOverlay.tsx
+++ b/frontend/src/common/components/map/S57EncOverlay.tsx
@@ -158,7 +158,10 @@ export function S57EncOverlay({ visible }: S57EncOverlayProps) {
 
       // sprite 등록 (중복 방지)
       if (!hasSprite(map, ENC_SPRITE_ID)) {
-        map.addSprite(ENC_SPRITE_ID, `${PROXY_PREFIX}/sprite/sprite`);
+        const spriteUrl = PROXY_PREFIX.startsWith('http')
+          ? `${PROXY_PREFIX}/sprite/sprite`
+          : `${window.location.origin}${PROXY_PREFIX}/sprite/sprite`;
+        map.addSprite(ENC_SPRITE_ID, spriteUrl);
       }
 
       // sources 등록 (타일 URL을 프록시로 치환)