PURPOSE: To improve the dimensional accuracy and surface quality by performing at least one of face reduction works having a specific ratio such as four-side rolling or die drawing, etc. on side parts of a flat wire stock in the initial or an optional stage of plural cold rolling works.

CONSTITUTION: In cold rolling of a flat steel, at least one of face reduction works having a 1.5W15% reduction ratio in the width direction are performed on side parts 5 of a flat steel with surface roughnesses of the sides 5 being kept small in the initial or an optional stage of cold rolling. One of four-side rolling, die drawing, and grooved rolling is performed as the face reduction work. By this method, both the dimensional accuracy and surface quality are improved.