PURPOSE: To provide a conductor heating device which can uniformly heat not only good conductor but also semiconductor, by applying a magnetic field to an object to be treated during transportation in the direction across the thickness.

CONSTITUTION: A heating part 18 in a heat insulated box 11 includes a plurality of air nozzles 20 for bearing the object to be treated 15 carried in from a carry-in port 13 and a certain appropriate number of rotors 21 to permit the object 15 to make self-emission of heat as a process of heat treatment. In these rotors 21 permanent magnets 24 are arranged so that magnetic poles are located alternately at the periphery of a cylinder 23 as a core, and permanent magnet material is magnetized for alternate appearance of magnetic poles. Thus a magnetic fluxe is generated directed outward from the surface of each rotor 21. An eddy current is generated in the object 15 confronting the rotors 21, and the heat emitted with this should subject the object 15 to necessary heat treatment.