diff --git a/src/hooks/roofcover/useAuxiliaryDrawing.js b/src/hooks/roofcover/useAuxiliaryDrawing.js
index ba631080..956bcf8f 100644
--- a/src/hooks/roofcover/useAuxiliaryDrawing.js
+++ b/src/hooks/roofcover/useAuxiliaryDrawing.js
@@ -22,6 +22,7 @@ import { useSwal } from '@/hooks/useSwal'
 import { booleanPointInPolygon } from '@turf/turf'
 import { usePopup } from '@/hooks/usePopup'
 import { calculateAngle } from '@/util/qpolygon-utils'
+import { QPolygon } from '@/components/fabric/QPolygon'
 
 // 보조선 작성
 export function useAuxiliaryDrawing(id) {
@@ -742,15 +743,38 @@ export function useAuxiliaryDrawing(id) {
     }
 
     const roofBases = canvas.getObjects().filter((obj) => obj.name === 'roofBase')
-    const innerLines = [...lineHistory.current]
+
+    //lineHistory.current에 있는 선들 중 startPoint와 endPoint가 겹치는 line은 제거
+    // 겹치는 선 하나는 canvas에서 제거한다.
+
+    const tempLines = [...lineHistory.current]
+    lineHistory.current = []
+    tempLines.forEach((line) => {
+      if (
+        lineHistory.current.some(
+          (history) =>
+            JSON.stringify(history.startPoint) === JSON.stringify(line.startPoint) &&
+            JSON.stringify(history.endPoint) === JSON.stringify(line.endPoint),
+        )
+      ) {
+        canvas.remove(line)
+        return
+      }
+
+      lineHistory.current.push(line)
+    })
+
+    const innerLines = lineHistory.current
 
     roofBases.forEach((roofBase) => {
+      const tempPolygonPoints = [...roofBase.points].map((obj) => {
+        return { x: Math.round(obj.x), y: Math.round(obj.y) }
+      })
       const roofInnerLines = innerLines.filter((line) => {
-        const turfPolygon = polygonToTurfPolygon(roofBase)
-
-        // innerLines의 두 점이 모두 polygon 안에 있는지 확인
-        const inPolygon1 = booleanPointInPolygon([line.x1, line.y1], turfPolygon)
-        const inPolygon2 = booleanPointInPolygon([line.x2, line.y2], turfPolygon)
+        const inPolygon1 =
+          tempPolygonPoints.some((point) => point.x === line.x1 && point.y === line.y1) || roofBase.inPolygon({ x: line.x1, y: line.y1 })
+        const inPolygon2 =
+          tempPolygonPoints.some((point) => point.x === line.x2 && point.y === line.y2) || roofBase.inPolygon({ x: line.x2, y: line.y2 })
 
         if (inPolygon1 && inPolygon2) {
           line.attributes = { ...line.attributes, roofId: roofBase.id }
@@ -759,6 +783,8 @@ export function useAuxiliaryDrawing(id) {
       })
 
       roofBase.innerLines = [...roofInnerLines]
+
+      canvas.renderAll()
     })
 
     closePopup(id)
diff --git a/src/util/qpolygon-utils.js b/src/util/qpolygon-utils.js
index 7ca7fb79..01140300 100644
--- a/src/util/qpolygon-utils.js
+++ b/src/util/qpolygon-utils.js
@@ -1034,9 +1034,10 @@ export const splitPolygonWithLines = (polygon) => {
     const routes = []
 
     // 시작점은 시작 hip라인의 출발점
-    const startPoint = point
+    const startPoint = { x: Math.round(point.x), y: Math.round(point.y) }
     // 도착점은 마지막 hip라인의 끝나는 점
-    const endPoint = polygon.points[(index + 1) % polygon.points.length]
+    let endPoint = polygon.points[(index + 1) % polygon.points.length]
+    endPoint = { x: Math.round(endPoint.x), y: Math.round(endPoint.y) }
 
     const startLine = allLines.find((line) => line.startPoint.x === startPoint.x && line.startPoint.y === startPoint.y)
     const endLine = allLines.find((line) => line.startPoint.x === endPoint.x && line.startPoint.y === endPoint.y)