The present invention provides an arrangement for enabling a plurality of central processing units to share specific resources while ensuring overall reliability owing to domain separation. More specifically, in a semiconductor data processing device comprising a plurality of access management circuits for managing access to resource units that are sharable by the central processing units via an internal bus, each of the access management circuits performs permission/inhibition control for access from the central processing units to the resource units according to a setting state of a domain setup register so as to allow domain separation of the resource units for each of the central processing units, and through use of a priority access permission control function for specific resource units selectively recognized by the access management circuits as resources sharable by the central processing units, access from one of the central processing units that is identified by register setting data is given higher priority than access from the other central processing units.