Abstract: A multilayer circuit board includes a plurality of substrates. Each of the substrates includes a thermosetting resin film having respective surfaces, a metal layer formed on the one of the surfaces and a thermoplastic polyimide film formed on the other surface. Each of the substrates has at least one via hole, which is filled with thermoplastic polyimide resin containing electrically conductive material to form an electrically conductive via. The metal layer is defined as a predetermined circuit pattern electrically connected to the via. The plurality of substrates are laminated in such a manner that the substrate is adhered to an adjacent one by means of the thermoplastic polyimide film.