An access control apparatus receives access requests from one or more regular masters and an irregular master and sequentially selects an access allowable target. Additionally, the access control apparatus calculates an amount of unused resources based on an amount of resources used by a regular master and a maximum amount of resources to be used by the regular master, and manages the unused resources. The access control apparatus selects an access request of an irregular master as an access allowable target when the irregular master makes the access request during a unit period and access based on an access request of at least one of the regular masters that has not been executed. The managed amount of unused resources is equal to or larger than an amount of resources which is to be used based on the access request of the irregular master.