Abstract: A magnetron driving power supply circuit comprising a control circuit. The control circuit includes a microprocessor for determining potential level of a reference voltage in response to detected signals from a current level detecting circuit and a voltage level detecting circuit. The control circuit also includes a triangular wave generator for outputting a signal to be compared with the reference voltage and generating a switching drive control signal. Therefore, the magnetron driving power supply circuit of the present invention can be applied to commercial power sources of different types without design modification.