An electrically conductive path is configured from a first copper plate, a second copper plate, and solder. The first copper plate has a first bent section extended from a first joining section joined to an electrically insulative board and bent toward the rear surface of the electrically insulative board. The second copper plate has a second bent section which is extended from a second joining section joined to the electrically insulative board, is bent toward the front surface of the electrically insulative board, and is disposed so as to cover, together with the first bent section, the inner wall surface of a base-material through-hole. Through-holes are provided in the portions of the second copper plate which face the inside of the base-material through-hole. Solder is filled between the first bent section and the second bent section.