A plurality of elongate warp-knit webs are connected side by side by water-soluble connecting threads along their longitudinal edges. The warp-knit webs are arranged in connected pairs each having a pair of opposed marginal edge portions for supporting a pair of rows of coupling elements, respectively. The connecting thread extends between and interconnects inner wales adjacent to the outermost wales in the opposed marginal edge portions in each pair of the warp-knit webs. The outermost wale is formed solely with a single thread and is shifted into contact with the inner wale, thereby providing a single widened wale along a longitudinal edge of the web. Between the opposed longitudinal marginal edges of the paired webs, there is a gap or clearance that is small enough to make a slide fastener sightly and resistant to being split open under accidental conditions.