PURPOSE: To obtain a copper-plated laminate equipped with an inner circuit inside it, wherein the laminate is less warped in a polishing process where its surface is polished or in an etching process where the inner circuit pattern is formed.

CONSTITUTION: A copper foil of 10 to 25% extensibility at a temperature of 180°C is provided to each side of a prepreg sheet, which is formed into an inner copper-plated laminate by thermocompression. The surface of the copper foil of the inner copper-plated laminate is then polished, an inner circuit pattern forming film is laminated thereon, the inner copper-plated laminate is exposed to light, the disused part of the copper foil is subjected to etching in the formation of an inner circuit pattern, and thus an inner circuit board is obtained. Then, a prepreg sheet is provided to each side of the inner circuit board, and a copper foil is provided to each outermost side of the inner circuit board, which is formed into a copper-plated laminate equipped with an inner circuit of nominal thickness ≤0.6mm by thermocompression.