A multifunction card device has an external connection terminal, an interface controller, a memory, and the security controller connected to the interface controller and the external connection terminal. The interface controller has a plurality of interface control modes, and controls an external-interface action and a memory interface action by the control mode according to the instruction from the outside. The external connection terminals have an individual terminal individualized for every interface control mode, and a communalized common terminal. A clock input terminal, a power supply terminal, and an earthing terminal are included in the common terminals. A data terminal, and a dedicated terminal of the security controller are included in the individual terminals. Partial communalization and individualization of an external connection terminal attain a guarantee of the reliability of an interface, and increase control of physical magnitude to some kinds of interface control modes. The security process by a security controller independent interface can also be guaranteed.