PURPOSE: To reduce the area required at the time of operating a mouse by returning a mobile section to a reference position when the external force applied to the mobile section disappears and, at the same time, stopping the sending of an electric signal for controlling the position of a cursor which has been sent until then.

CONSTITUTION: A mobile section 2 is displaced from a reference position and turned in the direction of an external force 6 when the section 2 is pressed to a plane and receives the force 6 in the direction parallel to the plane, and a detecting section 3 detects the displacement and displaced direction of the section 2 from the reference position. Then a converting section 4 converts the displacement and displaced direction into an electric signal for controlling the position of a cursor, and supplies the electric signal to a connected display device. When the force 6 disappears, the section 2 is returned to the reference position by means of a spring 5 and, at the same time, the section 3 detects that the displacement has disappeared. The section 4 stops the supply of the electric signal. Therefore, when a mouse 1 is operated, the movement of the mouse 1 is limited to the moving extent of the mobile section 2 and the area required at the time of operating the mouse can be reduced.