The invention is to alleviate cumbersome operations of manager such as registration and deletion of authentication information. A card ID read from an IC card is transmitted to an IC card authentication server to obtain a first authentication result, and when the first authentication result indicates a successful authentication, the use of a composite apparatus is permitted. When the first authentication result indicates a failed authentication, an input user name is transmitted to a directory service server to obtain a second authentication result, and, when the second authentication result indicate a successful authentication, the card ID failing the authentication and the user name succeeding in the authentication are transmitted for requesting a registration to an IC card authentication server, which, receiving the request, registers the card ID and the user name in the registration request in combination in an authentication table.