PURPOSE: To reduce an area necessary for mouse operation by providing the instruction inputting unit with a converting section for converting the magnitude of the displacement of a movable section to information about a traveling speed of the mouse and a signal generating section for converting information obtained from this converting section to an electric signal.

CONSTITUTION: An instruction inputting unit consists of a movable section 3 provided with the function that the movable section 3 is displaced by an external force from a predetermined reference position 1 and restored to the reference position 1, a sensing section 4 for sensing the presence or absence of a displacement from the reference position 1 of movable section 3 and the direction and magnitude of the displacement, a converting section 5 for converting the magnitude of the displacement of movable section 3 to information about traveling speed of a mouse, a signal generating section 6 for converting the information obtained from the converting section 5 to an electric signal. Accordingly, when operating the mouse, traveling of the main unit 2 of mouse is limited to a range where the displacement of movable section 3 occurs. With this, the area required for operating the mouse can be reduced, and also the traveling area of the cursor on the display can be changed by changing the magnitude of the displacement of movable section 3.