PURPOSE: To provide a microwave oven by which nonuniformity of heating and discharge in a wave guide can be prevented.

CONSTITUTION: In a radiating antenna 4, an upper edge part bends to the magnetron 1 side at ordinary time (around 100°C), and is formed so as to enter a hole 3a of a radiating antenna fixing plate 3. A lower end part bends to the heating chamber side. At abnormal time (around 200°C), the upper and lower edge parts are formed so as to bend to the heating chamber side in the middle in its radial direction. An inner peripheral side edge part of the radiating antenna 4 is bent to the heating chamber side at both ordinary time and abnormal time.