A fixing device which heats a heating object through induction heating by using a plurality of coils includes a plurality of coil drivers that drive the plurality of coils respectively, a drive circuit that controls ON/OFF states of a plurality of switching elements simultaneously to control the drive of the plurality of coil drivers, a control unit that controls a voltage supplied to each of the plurality of coils in accordance with the control of the ON/OFF states of the plurality of switching elements by the drive circuit, and a plurality of voltage control circuits that individually change the voltages supplied to the plurality of coils in accordance with the voltage control of the control unit.