PURPOSE: To provide the bus use right arbitration control system which eliminates the dead cycle of a bus use right arbitration cycle and improve the data transfer efficiency of a system bus as to a bus use arbitration control system for a decentralized processing system wherein plural processors are connected to a system bus and transfer data to one another.

CONSTITUTION: The processors 10 are connected to one another through the system bus 1, a system bus allocating circuit 30 arbitrates a right to use the bus, and the processors 10 transfer data to one another. This decentralized processing system is constituted by providing a processor logical connection information setting means 50 which can optionally set information showing which processor requests the right to use the system bus 1 and a processor number discriminating and generating means 40 which successively sends out processor numbers set by the processor logical connection information setting means 50 to the system bus 1 in the system bus allocating circuit 30.