PURPOSE: To easily and continuously change the ratio between the moving distance of a pointed position input device and that of a designated position on a screen by adjusting the distance between the input device and a plane in a working state of the input device and moving a contact point secured between a ball and a roller.

CONSTITUTION: A mouse main body is pressed strongly to a plane at the time of operating a mouse and a ball 1 is pushed onto a scanning surface 6. Thus the rollers 2a - 2d are expanded with pressure by the ball 1 since the circumferential surfaces of these rollers are tilted to each rotary axis. At the same time, the springs 4a - 4d are moved in their contraction directions. In other words, the rollers 2a - 2d slide along the encoder shafts 3a - 3d in accordance with the pressure produced between the ball and the plane and then move elastically in the longer circumferential sides of the rollers 2a - 2d. Thus the contact points between the ball 1 and the rollers 2a - 2d move to the shorter circumferential sides of the rollers 2a - 2d. Thus, the ratio between the shift distance of the position pointed by the mouse and that of a cursor on a screen can be easily and continuously changed in accordance with the pressure caused between the ball 1 and the plane.