PURPOSE: To improve close contactness between copper foil surface of external layer and photosensitive resin in manufacture of a printed wiring board.

CONSTITUTION: An oxidation processing step 5 and an electrical reduction processing step 6 to be conducted between a primary copper plating step 4 and a photosensitive resin laminating step 7 are described. For improvement of close contactness, in a laminating step of a multilayer printed wiring board, the surface of copper foil used for surface processing of internal layer plate is oxidized, and attention is paid to the blackening process to form a film of cupric oxide. Since the surface of this cupric oxide film includes fine protrusions and recesses, it is effective for improvement of close contactness between the photosensitive resin and copper foil surface at the time of forming a pattern. However, the cupric oxide film dissolves easily into an acidic solution, it is reduced to become an original metallic copper. Namely, cupric oxide film is electrically reduced in the alkali or neutral electrolyte to become a metallic copper condition, while leaving the fine protrusions and recesses of the cupric oxide.