diff --git a/cmd/view-map/main.go b/cmd/view-map/main.go
index 292f8e3..b1239e8 100644
--- a/cmd/view-map/main.go
+++ b/cmd/view-map/main.go
@@ -77,7 +77,7 @@ func main() {
 	win.OnKeyUp(ebiten.KeyDown, env.changeOrigin(+0, +64))
 	win.OnMouseWheel(env.changeZoom)
 
-	for i := 0; i <= 6; i++ {
+	for i := 0; i < 6; i++ {
 		win.OnKeyUp(ebiten.Key1+ebiten.Key(i), env.setZIdx(i+1))
 	}