An arbiter circuit includes a priority coefficient calculating unit, a priority coefficient comparator an acceptance determining unit, and a priority determining unit. The priority coefficient calculating unit calculates for each request an arbitration priority coefficient based on a priority level set for each request by requesters. The priority coefficient comparator compares arbitration priority coefficients calculated for the requesters by the priority coefficient calculating unit. The acceptance determining unit determines whether to accept the requests based on the comparison result by the priority coefficient comparator. When the arbitration priority coefficient calculated by the priority coefficient calculating unit is equal between two or more requests, the priority determining unit determines a priority order for accepting the requests.