PURPOSE: To enhance the converting efficiency, reduce noises and vibrations, and to raise the degree of freedom in designing by converting mechanical energy into thermal energy through the theory of electromagnetic inductive heating.

CONSTITUTION: A cylindrical rotor 3f consisting of magnetic electroconductive material is fixed to a rotary shaft 3b through a disc 3e. A group of permanent magnets 3g are fixed to a container 3c filled with a thermomedium 4 through a ring-shaped yoke 3h in such an arrangement that N and S poles are placed alternately in the circumferential direction. Because an alternating flux, chain crossing with the cylindrical rotor 3f with a micro gap interposed, is generated in the heat converter 3 by said group of permanent magnets 3g, an eddy current generated by electromagnetic inductive action flows through the cylindrical rotor 3f revolving, that involves a loss. That is to say, the wind energy transmitted to the rotary shaft 3b of the heat converter 3 through the windmill 1 is converted into thermal energy by means of the theory of electromagnetic inductive heating.