[Problem] To provide a surface-treated copper foil for a battery cell that is capable of providing good adhesiveness to an active substance and undergoes less detachment of roughening particles. [Solution] The surface-treated copper foil for a battery cell according to one or more embodiments of the present application contains a copper foil and a surface treatment layer on at least one surface of the copper foil, wherein the surface treatment layer contains a primary particle layer and a secondary particle layer, and the surface of the surface treatment layer has a ten-point average roughness Rz of 1.8 µm or more measured with a laser microscope with a wavelength of 405 nm according to JIS B0601 1994.