When changes occur in an environment of the service user terminal, a network operator terminal acquires hashed environment information indicative of the changes from the service user terminal. The network operator terminal sends the hashed environment information to an environment management authority terminal. The environment management authority terminal calculates an evaluation value based on the hashed environment information and transmits the evaluation value to a network operator terminal. The network operator terminal transmits status change information to the service provider terminal. The service provider terminal updates information about the user information previously stored and decides whether to provide the service to the service user terminal based on the updated information.