A surface-treated copper foil comprising an electrodeposited copper foil with a chromium-free rust-proofing layer which exhibits good performance in peel strength and resistance to peel loss after chemical treatment as a printed wiring board. The surface-treated copper foil comprises a rust-proofing layer and a silane coupling agent layer formed on an electrodeposited copper foil , wherein the rust-proofing layer comprises a nickel layer having a thickness by weight of 5 to 40 mg/m2 and a tin layer having a thickness by weight of 5 to 40 mg/m2 stacked in this order, and the silane coupling layer is applied on top of the tin layer. The surface-treated copper foil may be further coated with a very thin primer resin layer having a thickness of 0.5 to 5 μm.