diff --git a/service/imaging/processor_default.go b/service/imaging/processor_default.go
index f93a4f039..0a37fe91e 100644
--- a/service/imaging/processor_default.go
+++ b/service/imaging/processor_default.go
@@ -128,7 +128,7 @@ func (p *defaultProcessor) FitAnimationGIF(src io.Reader, width, height int) (*b
 		// 	ため、キャンバスでフレームを重ねてから縮小する
 		tempCanvas = image.NewNRGBA(gifBound)
 		// 	DisposalBackgroundに対応するための、背景色の画像
-		bgColorUniform = image.NewUniform(srcImage.Config.ColorModel.(color.Palette)[srcImage.BackgroundIndex])
+		bgColorUniform *image.Uniform
 		// DisposalPreviousに対応するため、直前のフレームを保持するためのキャンバス
 		backupCanvas = image.NewNRGBA(gifBound)
 
@@ -137,6 +137,12 @@ func (p *defaultProcessor) FitAnimationGIF(src io.Reader, width, height int) (*b
 		eg, _          = errgroup.WithContext(context.Background())
 	)
 
+	// グローバルカラーテーブルがあれば、背景色を取得
+	palette, ok := srcImage.Config.ColorModel.(color.Palette)
+	if ok && len(palette) > 0 {
+		bgColorUniform = image.NewUniform(palette[srcImage.BackgroundIndex])
+	}
+
 	for i, srcFrame := range srcImage.Image {
 		// 元のフレームのサイズと位置
 		//  差分最適化されたGIFでは、これが元GIFのサイズより小さいことがある
@@ -182,7 +188,7 @@ func (p *defaultProcessor) FitAnimationGIF(src io.Reader, width, height int) (*b
 			r, g, b, a := srcFrame.Palette[srcFrame.Palette.Index(color.Transparent)].RGBA()
 			if r == 0 && g == 0 && b == 0 && a == 0 {
 				draw.Draw(tempCanvas, srcBounds, image.Transparent, image.Point{}, draw.Src)
-			} else {
+			} else if bgColorUniform != nil {
 				draw.Draw(tempCanvas, srcBounds, bgColorUniform, image.Point{}, draw.Src)
 			}
 		case gif.DisposalPrevious: // DisposalがPreviousなら、直前のフレームを復元
diff --git a/service/imaging/processor_default_test.go b/service/imaging/processor_default_test.go
index 94552c965..dba6db097 100644
--- a/service/imaging/processor_default_test.go
+++ b/service/imaging/processor_default_test.go
@@ -121,6 +121,12 @@ func TestProcessorDefault_FitAnimationGIF(t *testing.T) {
 			want: lo.Must(io.ReadAll(testutils.MustOpenGif("frog_resized.gif"))),
 			err:  nil,
 		},
+		{
+			name: "success (surprised 正方形、グローバルカラーテーブルなし)",
+			file: "surprised.gif",
+			want: lo.Must(io.ReadAll(testutils.MustOpenGif("surprised_resized.gif"))),
+			err:  nil,
+		},
 	}
 
 	for _, tt := range test {
diff --git a/testdata/gif/embed.go b/testdata/gif/embed.go
index c3c37f02d..006c79ae1 100644
--- a/testdata/gif/embed.go
+++ b/testdata/gif/embed.go
@@ -20,3 +20,5 @@ var FS embed.FS
 // new_year.gif https://freesozaixtrain.web.fc2.com/freesozai-nenga-train2.html
 
 // tooth.gif https://patirabi.com/2021/10/10/061gif/
+
+// surprised.gif https://patirabi.com/2021/10/08/058gif/
diff --git a/testdata/gif/surprised.gif b/testdata/gif/surprised.gif
new file mode 100644
index 000000000..b3f57b9ce
Binary files /dev/null and b/testdata/gif/surprised.gif differ
diff --git a/testdata/gif/surprised_resized.gif b/testdata/gif/surprised_resized.gif
new file mode 100644
index 000000000..025ddc9aa
Binary files /dev/null and b/testdata/gif/surprised_resized.gif differ