There is provided a microwave irradiation apparatus capable of independently controlling a temperature of a target object while irradiating microwave to the target object. The microwave irradiation apparatus 2 includes a processing chamber 4 configured to be vacuum-evacuated; a supporting table 6 configured to support the target object; a processing gas introduction unit 106 configured to introduce a processing gas into the processing chamber; a microwave introduction unit 72 configured to introduce the microwave into the processing chamber; a heating unit 16 configured to heat the target object; a gas cooling unit 104 configured to cool the target object by a cooling gas; a radiation thermometer 64 configured to measure a temperature of the target object; and a temperature control unit 70 configured to adjust the temperature of the target object by controlling the heating unit and the gas cooling unit based on the temperature measured by the radiation thermometer.