A slide fastener in which fragments of coupling elements of the fastener are less likely to separate from the fastener when the fastener is forcibly split when an airbag is inflated and which has good appearance. The slide fastener (110) has coupling elements (12, 113) sewn to fastener tapes (16, 17), and the coupling elements (12, 113) each have first and second legs (72, 73) bifurcated and extending from a coupling head (70). A V-shaped cutout is formed in one part in an area extending from a sewing line (84) in a first sewing section (74) of the first leg (72) through the mating head (70) to a sewing line (85) in a second sewing section (75). This forms a weakened section (80) having intentionally reduced breaking strength. When excessive lateral force is applied to the slide fastener (110) to break the coupling elements (12) at the weakened sections (80), fragments of the coupling elements (12) are kept retained on the fastener tapes (16, 17).