An amplifier circuit for generating a predetermined constant voltage required for resetting organic EL elements or capacitors is provided and an operating current switching circuit switches the operating current of the amplifier circuit to an idling current in a display period and to a steady operation current required to performing a reset operation in a reset period, so that a shifting time of the amplifier circuit from the idling state to the steady operation state can be shortened and a constant control voltage for resetting the organic EL elements or the capacitors can be generated in an initial portion of the reset period.