PURPOSE: To manufacture a plane inductor having excellent heat dissipating characteristics and direct current superimposing characteristics by a method wherein the heat treatment is performed while feeding a current to plural coils so as to make the adjacent coils generate magnetic fluxes mutually in reverse directions and then magnetization facilitating axes of easy magnetization are given to ferromagnetic body foils.

CONSTITUTION: Four square spiral coils are juxtaposed on the same plane so that outer peripheral parts may take a larger square shape in twice as much length of one side of respective spiral coils to be connected for feeding a current making magnetic flux on adjacent coils mutually in reverse directions. Next, intensive magnetic body foils are overlapped on one or both surfaces of the coils in the central parts of the plane coils for heat treatment in magnetic field and then direct current is fed to the coils. Next, the heat treatment is performed at the temperature lower than the Curie temperature of the ferromagnetic body to give a magnetization facilitating axes turning in the peripheral direction to the ferromagnetic body foils. Furthermore, the coils may be miniaturized without restricting to the four coils.