PURPOSE: To provide a DC power supply equipment having an improved power factor, whereby its AC input current can be suppressed to a low value, without altering the constants of parts used in a conventional DC power supply equipment, by only adding a small number of parts to conventional ones, in the stabilized DC power supply equipment used for various electronic apparatuses.

CONSTITUTION: In a DC power supply equipment, a transformer 4 which follows conventionally the rectifier for an AC input power supply 1 is provided. The series circuit comprising a second switching element 13 and a capacitor 14 is connected in parallel with the series circuit comprising a primary winding 4a of the transformer 4 and a first switching element 5. In this configuration, when the AC input voltage is not lower than a certain voltage level V1, a current is fed from the AC input power supply 1, and when being not higher than the level V1, the current is fed from the capacitor 14 which has been charged to the peak value of the AC input voltage beforehand. Thereby, the power factor of the DC power supply equipment can be improved.