MICROWAVE OVEN

PROBLEM TO BE SOLVED: To provide a microwave oven applicable to various power source frequencies with one kind of high-voltage capacitor without using a high-voltage relay and prevents the abnormal temperature rise of a magnetron and the excessive heating of a material to be cooked. SOLUTION: At the time of the operation at 50 Hz of power source frequency, a DC relay 19 is held in the ON condition, and a power source is continuously applied from a high-voltage transformer 9 to a magnetron 23. At the time of the operation at 60 Hz of power source frequency, the DC relay 19 is turned on and off so that the power source is intermittently applied from the high-voltage transformer 9 to the magnetron 23. With this structure, a device can measure to a difference of a power source frequency with one kind of a high-voltage capacitor 25 without using a high-voltage relay. In the case where the DC relay 19 is left as it is turned on, this condition is discriminated on the basis of the temperature change ratio of the magnetron 23 immediately before turning off the DC relay 19 and the temperature change ratio of the magnetron 23 when the DC relay 19 is turned off, and the cooking is automatically stopped. Abnormal temperature rise of the magnetron 23 and the excessive heating of a material to be cooked can be thereby prevented.