A coupling element shaper comprises a pair of parallel externally threaded screw members corotatable in a common direction and disposed on opposite sides of a mandrel along which a core thread is fed while a filamentary material is wound around the mandrel into a row of helically coiled coupling elements. Each screw member has a portion varying in pitch to gradually reduce in a direction from one end to the opposite end thereof. The core thread is squeezed by the coupling elements as shaped by such portion so as to have a certain degree of stretchability which can cancel or take out its shrinkage when the coupling elements are sewn to a slide fastener stringer tape.