PURPOSE: To effectively carry out electromagnetic induction heating by promptly starting temperature rising through large consumption power due to the electromagnetic induction effect of the entire body of a magnetic heating layer, at the time of low temperature, and by eliminating the magnetic characteristic along with temperature rising, and whereby gradually reducing power consumption.

CONSTITUTION: When electrification is carried out to an annular coil 12 under a condition where a plate 13 that has magnetic property is put on an upper plate of a main body 11, electromagnetic induction is started between the plate 13 and the coil 12, and a magnetic heating layer 14 of the plate 13 is heated. Since the plate 13 is layered in such a way that the magnetism elimination temperature becomes lower as the magnetic heating layer 14 is farther outside on the plate 13, magnetism is gradually eliminated from the lower side of the plate 13 along with the temperature rising of the plate 13. The distance between the heating layer 14 heated by electromagnetic induction and the coil 12 which is an electromagnetic induction source of the main body 11, is widened, the electromagnetic work is automatically reduced. At low temperature, prompt starting of temperature rising is possible with large power consumption due to the electromagnetic induction of the entire body of the heating layer 14, while magnetism is gradually eliminated along with temperature rising, and power consumption is gradually reduced.