A separately-excited inverter circuit includes: an oscillator which generates a high-frequency voltage pulse by mixing a high-frequency voltage pulse of a first frequency and a high-frequency voltage pulse of a second frequency different from the first frequency; and a transformer drive part which buffers an output signal of this oscillator, and inputs the signal to a primary side of a transformer. The inverter circuit includes a capacitor which is connected in parallel with an output of a secondary side of the transformer. When used for lighting the backlight of a liquid crystal display, the present invention can improve the lighting characteristics of the backlight with a long cold-cathode tube.