Copper through-hole printed wiring boards are produced by forming an etching resist layer on the copper plating of a double sided copper clad laminate. The etching resist layer is formed after a negative resist pattern is applied to both sides of the laminate, and the laminate then dipped in a solution containing at least one salt of 2-alkylbenzimidazoles, 2-alkylalkylbenzimidazoles, 2-phenyl-benzimidazoles and 2-phenylalkylbenzimidazoles. After the resulting etching resist layer is selectively removed with an alkaline aqueous solution, in accordance with the predetermined pattern of the wiring, the exposed copper plating is etched off with an alkali etchant. According to the process of the present invention, remarkable advantages such as increased productivity, lower production costs, reduced toxic substances in waste water, and a high reliability can be obtained in the production of copper through-hole printed wiring boards.