To shift a backlight from its on-state to its off-state under a stable operation of a DC-DC converter by a comparatively simple constitution comprising a DC-DC converter and an inverter transformer.

A drive circuit is provided with a DC-DC converter 22 which forms pulsating voltage, an inverter transformer 24 for obtaining a transformed voltage based on the pulsating voltage, a feedback route forming part 25 which feeds the transformed voltage from the inverter transformer 24 back to the DC-DC converter 22, a dimming control unit 26 which performs dimming of a back light 20, a backlight on/off control unit 28 which performs state setting, so as to cause the backlight 20 to be in an on-state or off-state selectively, and a backlight on/off drive unit 27 which causes the DC/DC converter 22 to be selectively in an operating state or in a nonoperating state, in accordance with the state of the backlight on/off control unit 28.