To provide a mobile device which can be easily connected to a mobile equipment main unit, is hard to be affected by noises from the mobile equipment main unit and can fully perform GPS functions.

A controller box 2 contains a first integrated circuit IC22 on which a GPS receiver and a GPS antenna are mounted, and a second integrated circuit IC22, on which a control circuit for a controller is mounted. Furthermore, the controller box 2 is equipped with a music/voice terminal and a GPS terminal 22 which are connected to a headphone jack 21 and mobile equipment, respectively. The terminal 22 is inserted in the mobile equipment box 22, whereby a power source voltage VDD is applied from the mobile equipment box side 3, and the controller and the GPS functions become usable.