A knit slide fastener stringer comprising: a fastener tape (T) knit in a warp-knit ground structure and having along one longitudinal edge an element-attaching marginal portion (EA), and a continuous fastener element row (ER) knitted in and along the element-attaching marginal portion (EA) of the fastener tape (T) and secured by anchoring chain stitch yarns (1, 2) of at least two wales simultaneously with the knitting of the fastener tape (T). In the slide fastener stringer, an additional anchoring chain stitch yarn (6) independent from the anchoring chain stitch yarns (1, 2) is disposed between the anchoring chain stitch yarns (1, 2) near the coupling head portions (E-2) and successive coupling head portions (E-2), extending warpwise over the fastener element row (ER). And a connecting yarn (4a) extending weftwise substantially diagonally in gaps between adjacent fastener elements (E) from the upper side to the lower side connect the additional anchoring chain stitch yarn (6) with the ground structure of the fastener tape (T).