To provide a plating method for making the height of projecting defective parts fixed even with the lapse of time.

In the method for producing a copper-covered polyimide substrate by subjecting a polyimide substrate 1 whose surface has electric conductivity to copper plating by an electroplating process, each carrier roller 2 used in a copper plating liquid upon the electroplating has a shape where both the edge parts have the same large diameter parts 2-2, 2'-2, and the central part has a small diameter part 2-1, and also, only the insides of the large diameter parts 2-2, 2'-2 on both the edge parts in the carrier roller 2 are contacted with both the edge parts in the substrate 1.