When laminating two resin films so that sides where the conductive patterns are not formed face each other, and when laminating other resin films so that sides where the conductive patterns are formed and the sides where the conductive patterns are not formed to face each other, a plurality of resin films each of which has the same resin thickness are used for the other resin films, and two resin films having a sum of resin thickness that is the same as the resin thickness of the other single resin film are used for the two resin films. Accordingly, dielectric thicknesses between the conductive patterns formed in the adjoining resin films can be made even so that an impedance can be calculated easily, and it becomes possible to ease the circuit design.