An operation request from a process or OS for computer resource(s) managed by the OS, such as a file, network, storage device, display screen, or external device, is trapped before access to the computer resource. It is determined whether an access right for the computer resource designated by the trapped operation request is present. If the access right is present, the operation request is transferred to the operating system, and a result from the OS is returned to the request source process. If no access right is present, the operation request is denied, or the request is granted by charging in accordance with the contents of the computer resource.