A command receiver receives, from an external access requesting entity, a command with which to access data, together with an address to be accessed and IOID to identify the access requesting entity. Based on the IOID, the access decision unit determines whether or not an access is one that is to be permitted for an access requesting entity to access a region of access destination. The access decision unit determines whether access of the access requesting entity is permitted or not, for each page that serves as the basic management unit of logical address in the processor space.