The ballast of the present invention includes a DC power supply, an inverter circuit, a load circuit, and an integrated control circuit. The integrated control circuit controls the switching elements of the DC power supply and the inverter circuit. The integrated control circuit includes a first control unit, a second control unit, and a driver circuit. The first control unit generates a first control signal for control of the switching element of the DC power supply. The second control unit generates a second control signal for control of the switching elements of the inverter circuit. The driver circuit provides drive signals for driving each one of the switching elements of said DC power supply and the inverter circuit in accordance with the first control signal and the second control signal. As mentioned above, control circuits for controlling the DC power supply and the inverter circuit are integrated into a single component, the number of components which are mounted on a printed circuit board is reduced.