diff --git a/kadai1/shuntakeuch1/data/150x150.png b/kadai1/shuntakeuch1/data/150x150.png
new file mode 100644
index 0000000..32cf9f9
Binary files /dev/null and b/kadai1/shuntakeuch1/data/150x150.png differ
diff --git a/kadai1/shuntakeuch1/ifconv/ifconv.go b/kadai1/shuntakeuch1/ifconv/ifconv.go
new file mode 100644
index 0000000..cf62742
--- /dev/null
+++ b/kadai1/shuntakeuch1/ifconv/ifconv.go
@@ -0,0 +1,33 @@
+package ifconv
+
+import (
+	"image"
+	"image/jpeg"
+	"os"
+)
+
+func Execute(dir string, before_f string, after_f string) error {
+	sf, err := os.Open("test1.png")
+	if err != nil {
+		return err
+	}
+	defer sf.Close()
+
+	img, format, err := image.Decode(sf)
+	if err != nil {
+		return err
+	}
+
+	if format == "hoge" {
+		return err
+	}
+
+	file, err := os.Create("test1.jpeg")
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	jpeg.Encode(file, img, &jpeg.Options{})
+	return nil
+}
diff --git a/kadai1/shuntakeuch1/ifconv/ifconv_test.go b/kadai1/shuntakeuch1/ifconv/ifconv_test.go
new file mode 100644
index 0000000..7d96836
--- /dev/null
+++ b/kadai1/shuntakeuch1/ifconv/ifconv_test.go
@@ -0,0 +1,9 @@
+package ifconv
+
+import (
+	"testing"
+)
+
+func TestExecute(t *testing.T) {
+	Execute("foo", "bar", "hoge")
+}
diff --git a/kadai1/shuntakeuch1/main.go b/kadai1/shuntakeuch1/main.go
new file mode 100644
index 0000000..0a8d6dc
--- /dev/null
+++ b/kadai1/shuntakeuch1/main.go
@@ -0,0 +1,26 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/gopherdojo/dojo5/kadai1/shuntakeuch1/ifconv"
+)
+
+// flagをつけてbefore format と after formatのデフォルトをきめる
+var before = flag.String("b", "jpg", "変換前画像形式を指定してください")
+var after = flag.String("a", "png", "変換後画像形式を指定してください")
+
+func main() {
+	flag.Parse()
+	dir := flag.Arg(0)
+	// ディレクトリを聞く or 引数にないと強制終了
+	if dir == "" {
+		fmt.Println("ディレクトリを指定してください")
+		os.Exit(0)
+	}
+
+	result := ifconv.Execute(dir, *before, *after)
+	fmt.Println(result)
+}
diff --git a/kadai1/shuntakeuch1/test1.png b/kadai1/shuntakeuch1/test1.png
new file mode 100644
index 0000000..32cf9f9
Binary files /dev/null and b/kadai1/shuntakeuch1/test1.png differ