To provide an electrolytic copper foil for a secondary battery collector, which has a small surface roughness and uniform thickness in the width and length directions, is free from wrinkles after stretching and suppresses formation of discolored streaks along the length direction.

(1) An electrolytic copper foil for a secondary battery collector has 1.5% or less of difference in foil thickness in the width direction and shows no discolored streaks along the length direction on a surface of the copper foil. (2) The electrolytic copper foil for the secondary battery collector has 1.4% or less of difference in foil thickness in the width direction. (3) The electrolytic copper foil for the secondary battery collector shows 50% or less of variation in roughness (Rzmax-Rzmin)/Rzavg in the width direction of a matte surface.