PURPOSE: To rotate a cursor at the display.

CONSTITUTION: The motion of an input device is detected by a ball on it. A dial input means 30 which rotates the cursor at the display is added to a mouse which displays the cursor at the position on the screen according to the rotating direction and the rotating amount by outputting the rotating direction and the rotating amount of the ball. The dial input means 30 consists of a rotation control button 32, means 40 which moves it up and down, and detection means 52 connected to the button 32 and detecting the rotating direction and the rotating amount of it. Sometimes, when the cursor is within the prescribed coordinates, the button 32 is rotated and the cursor is rotated at the display according to the rotated amount. Thus, the rotating display of the cursor can be performed by the mouse.