The present invention relates to an electrolytic copper foil current collector where the surface properties are controlled to achieve a high adhesiveness to a negative electrode material. An electrolytic copper foil has a first surface and the second surface, the electrolytic copper foil comprising a first protective layer on the first surface side, a second protective layer on the second surface side, and a copper film between the first and second protective layers, wherein the coupling coefficient at the first surface or second surface of the electrolytic copper foil is 1.5 to 9.4 as represented by coupling coefficient=Rp/μm+ peak density/30+ amount of Cr adhesion/(mg/m2) (here, peak density is measured according to ASME standard B46.1). The electrolytic copper foil has a high adhesiveness to a negative electrode material and a low electrical resistance can be provided by controlling the surface properties of the electrolytic copper foil surface.