Abstract: An inventive regulated high-voltage power supply circuit comprises a push-pull oscillation circuit (30) including two transistors (TR4, TR5), a control circuit (20) for controlling voltage to be supplied to the oscillation circuit, a short detecting circuit (50) for detecting shorting in the secondary side of a high-voltage transformer thereby to attenuate output voltage from the control circuit and a time-constant circuit (60) for maintaining an attenuated state of the output voltage of the control circuit caused by the short detecting circuit after releasing of the shorting for a prescribed period of time. Since the osccillation circuit is of the push-pull type, the same can oscillate over the entire periods of positive and negative halfwaves of the AC waveform, thereby to increase outputted power.