PURPOSE: To keep strength suitable to an product and prevent the product from generating warpage by a method wherein a conductive molded piece with a large projected area and a small thickness is divided into a molded portion requiring conductive function and a base supporting said molded portion.

CONSTITUTION: A hole having a suitable shape and size (l1≥l2, l1/d≤75) is bored on a base plate 1 having a large projected area, a small thickness and a dimension ratio l>d>75 and a conductive molded piece having a suitable shape and size is provided on this hole portion. An insulating or conductive broad of thermosetting resin, thermoplastic resin, rubber or metal is used for the base 1 while powdery or fibrous material such as graphite, carbon black, etc. as conductive filler is used for conductive filler dispersion molding material, while thermosetting resin, thermo-plastic resin or rubber are used for resin component.