PURPOSE: To improve the adhesion in gilding to the resin surface of the inner periphery of a through hole by a method in which as the resin with which a prepreg is impregnated, the resin compounded with glass powder is used, and after the through hole has been drilled, the inside of the through hole is desmear-treated.

CONSTITUTION: A through hole 1 is formed on a metallic plate 2 by punch or drill working through the prepreg 3 impregnated with the resin compounded with glass powder and prepared, and several metallic plates 2 thus obtained are lapped and are formed under heating and pressurizing. While the through hole 1 of the metallic plate 2 is filled with resin 4, metallic foils 9 are respectively lapped and laminated on the upper and lower sides thereof. After a through hole 5 has been drilled on the resin part in the through hole 1 of the metallic plate 2, the inside of the through hole 5 is desmear-treated. Next, through hole gilding process is applied to the inner periphery of the through hole 5, whereby a through hole gilding layer is formed. This desmear treatment is the process removing the drill refuse of the resin adhering to the inner periphery of the through hole 5 formed in the circuit-position of a circuit plate 10, when the laminate is drilled. The resin is dissolved in sulfuric acid solution or permanganate acid solution, etc.