A switching substrate on which switching portions are mounted is attached at an angle to a case. The length in the pressing direction of a first push button of a push button unit is larger than the length in the pressing direction of a second push button. A first contact portion about which the push button unit rotates when the first push button is pressed and a second contact portion about which the push button unit rotates when the second push button is pressed are at substantially the same height from the surface of the switching substrate. Therefore, the rotation angle when a first operating surface is pressed can be made equal to the rotation angle when a second operating surface is pressed.