PURPOSE: To freely change a ratio of a moving extent of a mouse and a moving extent of a cursor by attaching an operable volume to the mouse.

CONSTITUTION: When a mouse 1 is moved on a plane, a rotational direction signal 13 and a rotational angle amount signal 14 are obtained from a detecting mechanism 12, based on a rotation of a rotating body 11. On the other hand, when a volume 2 is depressed, a sliding contact of a volume body 16 slides, and a volume signal 18 corresponding to a depressing amount of the volume 2 is obtained from a shaping circuit 17. Subsequently, by processing the signals 13, 14 and 18, a moving extent of a cursor 4 is determined. For instance, when the volume 2 is not depressed, a moving ratio to the mouse 1, of the cursor 4 is made small, and the more deeply the volume 2 is depressed, the larger the moving ratio of the cursor is made. In this way, a ratio of the moving extent of the mouse and the moving extent of the cursor can be changed freely.