Provided is an industrially excellent surface-treated copper foil which satisfies requirements for adhesiveness to an insulating resin such as polyimide, heat-resistant adhesiveness, chemical resistance and soft etching properties. Also provided is a method for producing a surface-treated copper foil which achieves a high adhesion strength between an insulating resin and the copper foil, shows high chemical resistance in circuit formation and sustains good soft etching properties after forming vias by laser-processing. A base copper foil is subjected to a roughening treatment to give a surface roughness (Rz) of 1.1 μm or below. On the roughened surface, an Ni—Zn alloy layer is formed. The aforesaid roughening treatment is conducted in such a manner that the roughened surface comprises sharp-pointed convexes, which have a width of 0.3-0.8 μm, a height of 0.6-1.8 μm and an aspect ratio of 1.2-3.5, and the surface roughness (Rz) of said base copper foil is increased by 0.05-0.3 μm. The aforesaid Ni—Zn alloy layer has a Zn content of 6-30 wt % and a Zn deposition amount of 0.08 mg/dm2 or more.