An object of the present invention is to provide a copper surface treatment method capable of keeping certainly a bonding strength between a copper surface and a resist, or between a copper surface and an insulating resin without forming irregularities having sizes of more than 1 μm on the copper surface, and a copper treated with the method. The surface treatment method, comprising: a first step of forming, on a copper surface, a nobler metal than the copper discretely; a second step, subsequent to the first step, of forming copper oxide on the copper surface by oxidation with an alkaline solution containing an oxidizing agent; and third step of dissolving the copper oxide so as to be removed, thereby forming irregularities on the copper surface.