diff --git a/resources/views/rd/fire-shutter-drawing/index.blade.php b/resources/views/rd/fire-shutter-drawing/index.blade.php
index cb9ca240..352befea 100644
--- a/resources/views/rd/fire-shutter-drawing/index.blade.php
+++ b/resources/views/rd/fire-shutter-drawing/index.blade.php
@@ -1359,8 +1359,8 @@ function renderSbSide() {
                 const lintelHookEnd = lintelShelfEnd + 20*sc; // 린텔 후크 끝 (15↑+20→)
                 const dx = lintelHookEnd; // 점검구 본체 시작 = 린텔 후크 끝 (플랜지가 20mm 립 위에 겹침)
                 const dy = oy + sH;        // 밑면 레벨
-                const doorEnd = ox + sD - (bRearW - vt)*sc; // 후면측 고정부 시작
-                const dw = Math.max(doorEnd - dx, sbDoorW * 0.8); // 본체 폭
+                const doorMainSpan = 385; // 하부 점검구 본체 폭 (500mm 깊이 기준)
+                const dw = doorMainSpan * sc; // 본체 폭 스케일 적용
                 const df17 = f17, df13 = f13;
                 return `
                     <!-- 본체 (밑면보다 13mm 아래, 트레이 바닥) -->
@@ -1373,10 +1373,13 @@ function renderSbSide() {
                     <rect x="${dx+dw-vt*0.7}" y="${dy}" width="${vt*0.7}" height="${df13+vt}" fill="${doorFill}" stroke="${doorStroke}" stroke-width="1" stroke-dasharray="4 2"/>
                     <!-- 우측 플랜지 (17mm →, 아래에서 후면측에 붙음) -->
                     <rect x="${dx+dw-vt*0.3}" y="${dy}" width="${df17+vt*0.3}" height="${vt*0.7}" fill="${doorFill}" stroke="${doorStroke}" stroke-width="1" stroke-dasharray="4 2"/>
+                    <!-- 치수선: 본체 ${doorMainSpan}mm -->
+                    <line x1="${dx}" y1="${dy+df13+vt+8}" x2="${dx+dw}" y2="${dy+df13+vt+8}" stroke="${doorStroke}" stroke-width="0.8"/>
+                    <line x1="${dx}" y1="${dy+df13+vt+3}" x2="${dx}" y2="${dy+df13+vt+13}" stroke="${doorStroke}" stroke-width="0.5"/>
+                    <line x1="${dx+dw}" y1="${dy+df13+vt+3}" x2="${dx+dw}" y2="${dy+df13+vt+13}" stroke="${doorStroke}" stroke-width="0.5"/>
+                    <text x="${dx+dw/2}" y="${dy+df13+vt+22}" fill="${doorStroke}" font-size="10" font-weight="900" text-anchor="middle" font-family="Pretendard">밑면 점검구 ${doorMainSpan}</text>
                 `;
             })()}
-            <!-- 밑면 점검구 라벨 -->
-            <text x="${ox+sD/2}" y="${oy+sH+16}" fill="${doorStroke}" font-size="9" font-weight="700" text-anchor="middle" font-family="Pretendard">밑면 점검구</text>
 
             <!-- ━━━━━ 레일 홀 (밑면 전면측 고정부 내) ━━━━━ -->
             ${(() => {