Before arbitration is performed in an arbitration section, an access from a master is kept in a waiting state until update of a conversion table buffer is performed, and an address conversion section is provided in a subsequent stage of the arbitration section. Without waiting for the completion of buffer update, an access is issued in advance at a time when it is assured that update is completed at the completion of address conversion. Thus, influences of waiting buffer update on another master can be eliminated and access latency can be reduced.