To provide a higher harmonic current reducing circuit where the drop of the conversion efficiency is improved, and the number of part items is reduced, and the econommzataon is achieved.

AC voltage from an AC power source 1 is half-wave-rectified with a rectifier diode 2, and this half-wave rectified voltage is switched with a switching element, and it is smoothed with an electrolytic capactor 12 through a high-speed recovery diode 8 before supply to a load 13, and also the switching element 9 is turned on/off so that the current from the AC power source may be sine waves through a drive circuit 10, based on the input voltage from an input voltage detecting circuit 5, the input current from an input current detecting circuit 7, and the output current from an output voltage detecting means 11.