An inverter driver controls an inverter that supplies driving voltages to a plurality of discharge lamps. The inverter driver includes a first amplifier having an output terminal, a second amplifier having an output terminal connected to the output terminal of the first amplifier, and a capacitor connected between the output terminal and a ground source. The first amplifier outputs only a negative current corresponding to the maximum value among the driving voltages supplied to the plurality of discharge lamps, and the second amplifier outputs a current corresponding to the maximum value among the driving currents flowing through the plurality of discharge lamps. Such inverter driver controls the inverter according to a voltage of the capacitor.