An administration server is capable of authenticating a user. The administration server includes a communication unit for receiving a user authentication request including user identification information and apparatus identification information from an external device; and a server control unit for authenticating the user according to the user identification information to obtain a first result. The server control unit is provided for determining a usage permitted function according to the user identification information to obtain a second result, and for determining whether an apparatus corresponding to the apparatus identification information can be used according to user identification information and the apparatus identification information to obtain a third result. The communication unit is configured to transmit the first result, the second result, and the third result to the external device.