PURPOSE: To prevent stop of current feed and raise the temp. of oil etc., in a short time by furnishing a top plate on its undersurface with a thermo- sensitive component to sense the bottom temp. of a deep pan to be heated, cooling with a fan, and thereby sensing eventual high temp. of the pan bottom.

CONSTITUTION: A thermo-sensitive component 6 to sense the bottom temp. of a deep pan to be heated 5 is furnished on the undersurface of a top plate 4 in the form of a flat plate covering the oversurface of a heater coil 2. A fan 7 is provided to cool this heater coil 2 and its surroundings, and a vent 9 confronting the thermo-sensitive component 6 is provided on a wind path 8, and thus the component 6 is cooled. When the deep pan 5 is filled for ex. with frying oil and heated by the coil 2, the component 6 is cooled to become a level equal to the oil temp. which is lower than the pan bottom temp. Thereby the component 6 senses the high temp. of the pan bottom to prevent stop of current feed to the heater coil 2, and the oil temp. can effectively be raised in a short time.