When forming a resin material in a through hole, an electrode pad is formed in the bottom portion of the through hole, an insulating material is formed about the periphery of the through hole and a conductive material is formed in the central portion by an inkjet method, inkjet-ejected resins being ejected in such a manner that concavo-convex indentations and projections are formed in the surface thereof, whereby the adhesiveness between the insulating material and the conductive material and the adhesiveness between the insulating material and the inner walls of the through hole can be improved. Therefore, it is possible to suppress mechanical defects such as detachment of conductive material at the interfaces between the inner surface of the through hole and the resin or conductor layer, or electrical defects such as insulation defects, conduction defects, or the like.