Both RF communication and contact serial communication can be performed with the use of: communication protocol storage unit for storing a communication protocol for performing communication with an external communication apparatus; a coil terminal section provided with two coil terminals for performing communication with the external communication apparatus with an RF signal; a contact communication terminal section provided with a first communication terminal, a second communication terminal, a power supply voltage terminal and a ground terminal as contact communication terminals for performing contact communication with the external communication apparatus; and connection control unit for causing the power supply voltage terminal and a power supply of an internal switch circuit to be in contact or non-contact with each other depending on the level of voltage applied to the first and second communication terminals.