PURPOSE: To obtain sufficient amount of heat generation even when a current, conducted through a transmission and/or distribution line, is small by a method wherein a plurality of magnetic element sheets, having the thickness of 0.5mm or less and coated with insulation coating, is laminated to obtain a laminated magnetic body while the periphery of the laminated magnetic body is coated with an electroconductive coating.

CONSTITUTION: A magnetic element sheet 1, consisting of a magnetic metal or alloy, is worked so as to be a thin plate having the thickness of 0.5mm or less. The surface of respective magnetic element sheets 1 is coated with an insulation film 2 while a plurality of the magnetic element sheets 1 is laminated to constitute a laminated magnetic body 4. The periphery of the laminated magnetic body 4 is coated with a coating body 3 consisting of an electroconductive metal or alloy. According to this method, eddy currents, generated in the ferromagnetic element sheet 1, is reduced than the same so far and the magnetization of the magnetic element sheet 1 may be advanced more quickly. Accordingly, the density of flux, trapped on the periphery of the laminated magnetic body 4, is increased and the rate of changing of the flux may be increased. As a result, eddy corrects generated in the coating body 3, is increased thereby increasing the heat release value due to a Joule loss.