diff --git a/B06_Section/B06_Section_Engine_Culvert.py b/B06_Section/B06_Section_Engine_Culvert.py
index ce97262f9..87fb59003 100644
--- a/B06_Section/B06_Section_Engine_Culvert.py
+++ b/B06_Section/B06_Section_Engine_Culvert.py
@@ -327,7 +327,8 @@ def _wing_spec(values: dict[str, Any], defaults: dict[str, Any], side: str) -> d
     height = _number(
         values.get(f"{prefix}_height_m"), _number(defaults.get(f"{prefix}_height_m"), 0.0)
     )
-    installed = str(install or "").strip() != "없음"
+    # BOX암거 유입·유출 구조(표 02) — 없음 · 날개벽 · 흙막이 · 옛 값 있음 = 날개벽. 날개벽만 세움.
+    installed = str(install or "").strip() not in ("없음", "흙막이")
     extend = (length or 0.0) * math.cos(math.radians(angle or 0.0)) if installed else 0.0
     return {
         "installed": installed,
diff --git a/common_util/common_util_culvert_sets.ts b/common_util/common_util_culvert_sets.ts
index f9055b0ac..d53993a58 100644
--- a/common_util/common_util_culvert_sets.ts
+++ b/common_util/common_util_culvert_sets.ts
@@ -241,7 +241,8 @@ function wingSpec(
   const length = num(values[`${prefix}_length_m`], num(defaults[`${prefix}_length_m`], 0.0));
   const angle = num(values[`${prefix}_angle_deg`], num(defaults[`${prefix}_angle_deg`], 45.0));
   const height = num(values[`${prefix}_height_m`], num(defaults[`${prefix}_height_m`], 0.0));
-  const installed = String(install ?? "").trim() !== "없음";
+  // BOX암거 유입·유출 구조(표 02) — 없음 · 날개벽 · 흙막이 · 옛 값 있음 = 날개벽. 날개벽만 세움.
+  const installed = !["없음", "흙막이"].includes(String(install ?? "").trim());
   return {
     installed,
     height_m: height,
diff --git a/resources/tester/test_b06_box_set.py b/resources/tester/test_b06_box_set.py
index c88753e6c..ca213b8a2 100644
--- a/resources/tester/test_b06_box_set.py
+++ b/resources/tester/test_b06_box_set.py
@@ -45,6 +45,14 @@ def test_box_wing_extends_slab() -> None:
     assert spec["wing_in"]["slab_extend_m"] == round(2 * math.cos(math.radians(45)), 3)
 
 
+def test_box_structure_choices() -> None:
+    """유입·유출 구조(표 02) — 날개벽 · 옛 값 있음만 날개벽을 세움 · 흙막이 · 없음은 안 세움."""
+    for value, installed in (("날개벽", True), ("있음", True), ("흙막이", False), ("없음", False)):
+        spec = _box_set({"wing_in": value, "wing_in_length_m": 2})
+        assert spec["wing_in"]["installed"] is installed
+        assert (spec["wing_in"]["slab_extend_m"] > 0) is installed
+
+
 def test_attach_box_only_owner_station(tmp_path: Path) -> None:
     """BOX암거는 **소유 측점 한 곳에만** `box` 키로 붙는다(2026-08-25 사용자 확정).
 
diff --git a/resources/tester/test_b06_culvert_sets_mirror.py b/resources/tester/test_b06_culvert_sets_mirror.py
index b92cc6499..9ddacc95d 100644
--- a/resources/tester/test_b06_culvert_sets_mirror.py
+++ b/resources/tester/test_b06_culvert_sets_mirror.py
@@ -58,7 +58,13 @@ POINTS = [
     {
         "chainage_m": 80.0,
         "facility": "box_culvert",
-        "options": {"body_width_m": 3.0, "body_height_m": 2.5, "wing_out_length_m": 2.0},
+        "options": {
+            "body_width_m": 3.0,
+            "body_height_m": 2.5,
+            "wing_in": "날개벽",
+            "wing_out": "흙막이",
+            "wing_out_length_m": 2.0,
+        },
     },
     {
         "chainage_m": 100.0,