According to the present invention, a user's portable telephone 11 accesses a content provider 19 (S1); if the user's portable telephone 11 is registered in a user menu information database 35, a requested content service is immediately provided (S2); if it is unknown whether the portable telephone 11 is registered in the user menu information database 35, a request is made of a communications carrier 31 that it be determined whether the user is registered in the user menu information database 35; if the user's portable telephone is not registered, a request to perform registration is made (S3); the communications carrier 31 provides information that the user's portable telephone 11 is now registered (S6); and the requested content service is provided to the user's portable telephone 11 (S2).