MICROWAVE OVEN

PROBLEM TO BE SOLVED: To prevent abnormal temperature rise of the inside of a machine chamber in which a high-pressure relay for switching capacitance of a high- pressure capacitor is arranged in a multiplied voltage rectifying circuit for driving a magnetron during heater heating cooking. SOLUTION: A control unit 37, in case that a power frequency is 60Hz as specified, always interrupts power of a high-pressure relay 9 arranged in a machine chamber adjacent to a cooking chamber and turns off a normal open contact 9a, thereby reducing capacitance of a high-pressure capacitor 34 in a multiplied voltage rectifying circuit 36 for driving a magnetron 7, and in case that a power frequency is 50Hz that is out of the specification, contacts power of the high-pressure relay 9 only during micro-oven cooking due to the magnetron 7 and turns on the normal open contact 9a, thereby increasing capacitance of the high-pressure capacitor 34. Consequently, in case that the power frequency is 50Hz that is out of the specification, since the high-pressure heater is power-interrupted during heater heating cooking, that magnetizing coil 9C is never conducted and heated, and the inside of the machine chamber does not rise a temperature abnormally even if it is subject to thermal influence of heater heating cooking.