Abstract: A power supply apparatus has a full-wave rectifier for rectifying an AC voltage from an AC power source to output a DC pulsating voltage, and a high-frequency inverter which performs an oscillating operation to generate an output voltage. A first capacitor is connected between the output terminals of the full-wave rectifier, a diode is connected to one end of the first capacitor and is forward-biased with respect to the pulsating voltage from the full-wave rectifier, a second capacitor is connected in parallel with the first capacitor through the diode, and an oscillation circuit, including a series circuit formed of an inductor and a charging capacitor is connected in parallel with the second capacitor, for storing a DC voltage lower than a peak value of the pulsating voltage from the full-wave rectifier in the charging capacitor.