To provide an etching liquid for copper or a copper alloy capable of producing an electronic substrate in which side etches are reduced, the narrowing of the upper part of copper wiring is suppressed, and short circuits are not generated, and to provide a method for producing an electronic substrate using the same.

In the method for producing an electronic substrate, a copper layer (2a) formed on an electrically insulated base material (1) is etched so as to be a prescribed shape to form copper wiring (2c). After the main etching, copper (A) to be removed remaining in the cuff part of copper wiring (2b) is removed with an aqueous solution comprising (a) an oxidizer for copper by 1 to 50 g/L, (b) at least one kind of acid selected from the group consisting of hydrochloric acid and organic acid by 1 to 200 g/L, and (c) at least one kind of polymer selected from the group consisting of polyalkylene glycol and a copolymer of polyamine and polyalkylene glycol by 0.01 to 50 g/L.