diff --git a/tuhigui/window.py b/tuhigui/window.py
index 24d022b..7a1b35c 100644
--- a/tuhigui/window.py
+++ b/tuhigui/window.py
@@ -131,6 +131,7 @@ class MainWindow(Gtk.ApplicationWindow):
     def __init__(self, **kwargs):
         super().__init__(**kwargs)
 
+        self.maximize()
         self._tuhi = TuhiKeteManager()
 
         action = Gio.SimpleAction.new_stateful('orientation', GLib.VariantType('s'),