An RF energy radiation device includes a cavity in which a heating target object is to be placed, an RF signal generation unit, an RF amplifier, a radiation element, a temperature sensor, and a controller. The RF signal generation unit oscillates an RF signal. The RF amplifier amplifies the RF signal and provides RF energy. The radiation element radiates the RF energy into the cavity. The temperature sensor is disposed in the vicinity of the RF amplifier. The controller controls the RF amplifier so that the RF amplifier adjusts the RF energy output in accordance with the temperature detected by the temperature sensor and a plurality of threshold levels. This aspect can improve the reliability of the device.