An electric device includes at least one or more processing units that perform a predetermined process; a power-supply control unit that controls supply of electric power from a power source to the processing units and shutoff of the supply; a main control unit that performs a start-up process if the main control unit is supplied with power from the power source; and a sub control unit that controls the power-supply control unit so as not to supply the electric power to all or some of the processing units after the start-up process.