To provide a high voltage power supply ensuring a desired operation and an air cleaner in which dust collecting function is enhanced and a desired air cleaning function is attained by employing that high voltage power supply.

The high voltage power supply comprises a power supply and a transformer and generates a high voltage on the secondary of the transformer wherein a pulse generator is provided on the primary of the transformer. The pulse generator comprises a controller for generating a signal forming a pulse waveform and the controller varies the duty ratio of HI and LOW and varies the output voltage according to the duty ratio.