To improve processing performance of an information processing device as a whole by controlling priority in units of processes. There are provided a bus for data transfer and a plurality of function modules each having a processing function performing processing in units of processes and capable of issuing a data transfer request for the bus. Further, there is provided a process identification information holding unit capable of holding process identification information set for each of the processes in association with the function module performing processing of the process. Furthermore, there is provided a bus arbiter determining a priority order of processing for each piece of the corresponding process identification information for each data transfer request from the function module and arbitrating contention of data transfer requests for the bus according to the priority order. Processing performance is improved by performing priority order control in units of processes.