To change the relation of the shift distance of a mouse and a cursor by adjusting it to a work content by providing a plurality of parts detecting the shift distance of the mouse and permitting the detection parts to output signals showing the different shift distances to the same signal line.

A first ball 11 is touch-rotated at the time of use in a regular shift distance. A first Y-axis encoder 12 and an X-axis encoder 13 emit pulse signals with the rotation as shift quantity data in the directions of Y and X- axes. A second ball 14 touch-rotates with a desk at the time of changing the shift distance. A second Y-axis encoder 15 and an X-axis encoder 16 emit pulse signals with the rotation as shift quantity data in the directions of the Y and X-axes. A Y-axis encoding signal synthesis circuit 17 synthesizes the pulse signals of the Y-axis encoders 12 and 15 into one signal and an X-axis encoding signal synthesis circuit 18 similarly synthesizes the pulse signals of the X-axis encoders 13 and 16 into one signal. A mouse interface circuit 19 converts the synthesized pulse signals into the electric signals of interface specification.