Server device 60 stores contract identification information with UIM (Universal Identity Module) identification information for identifying a UIM 20 issued in accordance with a subscription contract between a subscriber and a communication carrier for services provided by the communication carrier, the contract identification information identifying the subscription contract. The UIM 20 stores UIM identification information. After receiving the UIM identification information from the mobile station 30, which obtained the UIM identification information from UIM 20, server device 60 transmits the contract identification information corresponding to the UIM identification information to the mobile station 30. Then the contract identification information is stored in UIM 20. Consequently, the present invention allows a communication apparatus to distinguish a user who attempts to use the communication apparatus.