A first stack is formed by stacking a first sheet of metal foil, a first prepreg, and a second sheet of metal foil, one on top of another. The first prepreg is thermally cured by thermally pressing these members to make a double-sided metal-clad laminate. Conductor wiring is formed by partially removing the first sheet of metal foil from the double-sided metal-clad laminate to make a printed wiring board. After a third sheet of metal foil has been preheated, the conductor wiring of the printed wiring board, a second prepreg, and the third sheet of metal foil are stacked one on top of another and thermally pressed together. The first insulating layer has a lower linear expansion coefficient than any of the first sheet of metal foil or the second sheet of metal foil does.