PURPOSE: To obtain the titled steel wire or steel cord having improved moisture- resistant adhesivity to rubber and suitable for tire, etc., enabling the reduction of the thickness of plating while suppressing the peeling of plating in wire drawing, by carrying out electropolishing smoothing of wire surface as pretreatment of plating process.

CONSTITUTION: As a pretreatment process for the drawing of element wire, a surface scale is removed from the element wire by acid cleaning with hydrochloric acid, sulfuric acid, etc., or electrolytic cleaning and the wire is subjected to electropolishing in an aqueous solution composed mainly of phosphoric acid and mixed with sulfuric acid,etc., until the average surface roughness of the wire reaches ≤1μm. The polished wire surface is plated with a Cu-Zn binary alloy or ternary alloy obtained by adding Ni, Co, Fe or Sn to Cu-Zn system. The thickness of the plating is selected to satisfy the formula, i.e. to give a drawn wire having a plating thickness of 0.05W0.2μm.