The present invention relates to a steel cord for rubber reinforcement. In the steel cord of the present invention, cobalt is contained by 0.001 ppm to 0.1 ppm within a 4 nm top-surface of the brass-plated steel wire. A method of manufacturing the steel cord includes: providing a brass-plated steel wire; mixing a cobalt compound in a wet lubricant filled in a wet drawing bath provided with a plurality of drawing dies between one pair of multi-stage drawing cones such that the concentration of the cobalt compound becomes 0.1 ppm to 100 ppm; and causing the cobalt to be contained by 0.001 ppm to 0.1 ppm within a 4 nm top-surface of the brass-plated steel wire after the brass-plated steel wire passes through a final die by causing the cobalt to be attached to a surface of the brass-plated steel wire and alloyed with a brass layer while the brass-plated steel wire is passing through the drawing cones and the drawing dies to be subjected to multi-stage drawing.