To provide an electrolytic copper foil capable of reducing any warp caused by the thermal load, in particular, an electrolytic copper foil useful for a secondary battery negative electrode current collector, and a method for manufacturing the same.

In the method for manufacturing the electrolytic copper foil 4, for the electrolytic copper foil 4, the difference in Vickers hardness (Hv) of the front and the back surfaces of the electrolytic copper foil 4 or the electrolytic copper foil 4 after treatment is ≤10. In the electrolytic copper foil 4, the warp of the electrolytic copper foil 4 or the electrolytic copper foil 4 after the treatment is ≤1 mm. The electrolytic copper foil 4 or the electrolytic copper foil 4 after the treatment is heated in an oven at the temperature of 130-155°C, and the distortion of the electrolytic copper foil 4 or the electrolytic copper foil 4 after the treatment is removed.