A DC-DC converter and first and second bypass switch circuits are provided in parallel between an input pin and first and second output pins and operate in accordance with a combination of the voltage value of the input pin and the voltage value required for the first output pin. A start control circuit causes the DC-DC converter to operate unconditionally in a step-down mode during the period from when the DC-DC converter is started until the output voltage of the DC-DC converter becomes equal to the voltage of the input pin. An output slope control circuit synchronizes rising slopes of the output voltages of the first and second bypass switch circuits with a rising slope of the output voltage of the DC-DC converter.