diff --git a/TIASshot/ColorCorrection/ColorCorrector.cs b/TIASshot/ColorCorrection/ColorCorrector.cs
index 74bd7e8..4c37829 100644
--- a/TIASshot/ColorCorrection/ColorCorrector.cs
+++ b/TIASshot/ColorCorrection/ColorCorrector.cs
@@ -162,10 +162,15 @@
         /// <param name="img">画像</param>
         /// <param name="target">変換目標の24x3行列</param>
         internal Mat CalcConvertMatrix(Mat src, Mat target, int channels) {
+            // ExtendMat は非対応入力で src をそのまま返すため，新規確保時のみ解放する
             var extended = ExtendMat(src, channels);
-            Mat convMat = new Mat(channels, 3, MatType.CV_64FC1);
-            Cv2.Solve(extended, target, convMat, DecompTypes.SVD);
-            return convMat;
+            try {
+                Mat convMat = new Mat(channels, 3, MatType.CV_64FC1);
+                Cv2.Solve(extended, target, convMat, DecompTypes.SVD);
+                return convMat;
+            } finally {
+                if (!ReferenceEquals(extended, src)) extended.Dispose();
+            }
         }
 
         /// <summary>
@@ -175,9 +180,15 @@
         /// <param name="conv"></param>
         /// <returns></returns>
         internal Mat ConvertColor(Mat src, Mat conv) {
+            // ExtendMat は非対応入力で src をそのまま返すため，新規確保時のみ解放する
             var extended = ExtendMat(src, conv.Rows);
-            var converted = (extended * conv);
-            return converted.ToMat();
+            try {
+                using (var converted = extended * conv) {
+                    return converted.ToMat();
+                }
+            } finally {
+                if (!ReferenceEquals(extended, src)) extended.Dispose();
+            }
         }
 
         /// <summary>