According to various embodiments, an electronic device may include a first structure including a first plate including a first surface and a second surface facing away from the first surface, and at least one side surface, a second structure including a second plate facing the second surface of the first plate; a first side wall extended to the second plate; a second side wall extending to the first side wall and the second plate and facing the side surface; and a third side wall extending to the first side wall and the second plate, parallel to the second side wall and facing the side surface, wherein the second plate, the first side wall, and the second side wall and the third side wall together form a trough with one side opened to receive at least part of the first structure, the first structure is movable between an open state and a closed state with respect to the second structure in a first direction parallel to the second plate and the second side wall, and the first structure is placed at a first distance from the first side wall in the closed state, and placed at a second distance which is greater than the first distance from the first side wall in the open state, at least one mechanical button mounted on the second side wall, and moving toward the first structure from outside of the second structure, and a sensing circuit disposed between the side wall and the second side wall with at least partial area, and configured to detect the movement of the mechanical button. Besides, various embodiments are possible.