A high voltage generating circuit includes a boosting portion (e.g., a trigger coil (22)) for boosting DC voltage delivered from a DC power supply (26) so as to deliver high voltage at a secondary side, a switching element (e.g., a MOS FET (23)) for turning on and off current flowing in the primary side of the boosting portion, and a pulse signal generating portion (24B) for generating a pulse signal for controlling on and off of the switching element.