molding a magnetic material with a base material into an intermediate body including the base material and a substrate body, the base material including a first part and a second part, the first part being surrounded by the substrate body, the second part of the base material being exposed from the substrate body on either side thereof, a main component of the base material being a metal having a lower ionization tendency than iron, the substrate body containing a plurality of metal magnetic particles, a main component of the metal magnetic particles being iron;

after the molding of the intermediate body, bending the second part of the base material on either side into a conductor portion such that the conductor portion includes (i) a buried part surrounded by the substrate body, (ii) an exposed part situated outside the substrate body on either side and (iii) a connecting part connecting the buried part and each exposed part;

after the bending, heating the intermediate body at a first temperature, so that an oxide film containing an oxide of the metal having a lower ionization tendency than iron is formed to cover a surface of the conductor portion; and

after the heating at the first temperature, heating the intermediate body at a second temperature higher than the first temperature (i) to form an oxide coating film containing iron oxide on a surface of each of the metal magnetic particles so that the substrate body is formed into a magnetic base body, (ii) to form the oxide film into an insulating oxide layer containing iron oxide and the metal, and (iii) to anneal the conductor portion.