To enable a cooperated mouse operation even in the same window by arranging painters in respective windows in multiwindow environment and enabling multitask processing.

Indication signals from transmission parts 30A and 30B when wireless mice 3A and 3B and respective indication buttons are operated are received by reception parts 10A and 10B, and mouse control circuits 11A and 11B cooperate pointers in windows with the wireless mice. An input detecting circuit 12 processes input signal from a keyboard 2 and the wireless mice 3A and 3B and a signal control circuit 13 which inputs its result monitors the operation state of the keyboard 2, etc., with the process signal of the input detecting circuit 12 and inputs information conforming to respective instructions to a CPU 14. A painter control circuit 15 calculates the positions of the wireless mice 3A and 3B and the movement quantities of the pointers and sends them to an image forming circuit 16, so that output data of a painter control circuit 15 is outputted as an image to a display 4.