There is provided a copper foil having a surface coating layer that can achieve a high bonding strength to a resin layer even if the copper foil has an extremely smooth surface such as one formed by vapor deposition, for example, sputtering and also has a desirable insulation resistance suitable for achieving a fine pitch in a printed wiring board. A surface-treated copper foil according to the present invention includes a copper foil and a silicon-based surface coating layer provided on at least one surface of the copper foil, the silicon-based surface coating layer being mainly composed of silicon (Si). The silicon-based surface coating layer has a carbon content of 1.0 to 35.0 atomic % and an oxygen content of 12.0 to 40.0 atomic % relative to a total content in 100 atomic % of carbon (C), oxygen (O) and silicon (Si) elements as measured by X-ray photoelectron spectroscopy (XPS).