A management server receives first user identification information and designation information for designating a service which are sent from a user terminal; detects specific information corresponding to a service provider which provides the desired service from a database containing specific information uniquely assigned to each service provider; generates second user identification information based on the detected specific information and the first user identification information; and then transmits the second user identification information to the user terminal. Using the second user identification information, the user terminal accesses the server of the service provider providing the desiring service. This prevents important information such as device IDs from being used when a user receives a service through a network from a service provider other than device manufacturers, and relieves the burden on such service provider upon providing a service.