To obtain a steel cord for a radial tire, good in rubber penetrability and excellent in strength or fatigue resistance by locating coil parts of the other wire between the respective winding pitches of a pair of spiral wires mutually different in winding directions, bringing down the coil parts into a flat state and composing the steel cord.

This steel cord is obtained by keeping a right hand spiral wire 1 and a left-hand spiral wire 1' continuously formed of coil parts 100 mutually different in winding directions in an engaged state so as to locate the coil parts 100 of the other wire between the respective winding pitches, simultaneously bringing down the coil parts 100 and forming the wires 1 and 1' into a flat shape at 25-50% flatness ratio as a whole. Thereby, the resultant steel cord has an ultrahigh elongation and characteristics gold in follow-up properties to unevenness and is suitable for reinforcing rubber such as a tire.