Method of manufacturing laminate body by: curing thermosetting resin composition on a support; laminating the curable resin onto a substrate; heating the laminate; forming a via hole in the cured resin layer; peeling the supporting body from the cured composite; performing a second heating of the cured composite; removing resin residue in the via hole of the cured composite; and forming a conductor layer on an inner wall surface of the via hole by electroless plating or a combination of electroless plating and electrolytic plating.