PURPOSE: To prevent the attachment of boiled soup and oil, by supporting a sensor guide by a sensor mounting table and a supporting post so that the guide can be slidden up and down, slidably mounting a heating head at the upper end of the guide, and enclosing springs in the sensor guide.

CONSTITUTION: The temperature sensor 3 is provided at the center of a burner 1 and a heat shielding tube 2, and a cooking container is mounted on the burner 1. Then the outer bottom surface of the cooking container is contacted with the temperature sensor 3. The temperature change is detected by a thermocouple 20. The springs 13 and 17 are accommodated in the upper and lower ends of the sensor guide 9. The heat sensitive head 15 is closely contacted with the cooking container. The outer diameters of the heat sensitive head 15 and an umbrella body 21 are larger than the diameter of a protruded part 8 of a guide hole 7 in a sensor mounting plate 6. Even though the boiled soup and oil spill down from the cooking container, they are not attached to the movable parts such as the sliding surface of the temperature sensor 3 and the springs.