PURPOSE: To use plural input devices simultaneously by performing selecting operation or vector composition for push-button operation signals and signals of movement quantities from plural input devices and sending the result to a host system by a CPU.

CONSTITUTION: The CPU 3 connects with a ROM for holding a processing program, a RAM used for arithmetic processing, and plural serial interface controllers 8, 9, and 10. Further, the CPU 3 performs multitasking processing with interrupts from serial interface ports 6 and 7 according to the processing program in the ROM and receives signals at the same time. The signals from input devices 4 and 5 are sent to the host system as an output signal from a single input device through a serial interface port 1 after the CPU 3 selects the signals and performs the vector composition of their movement quantities. Consequently, individual operators are enabled to occupy the input devices individually.