Slide Fastener

A slide fastener comprising:

• a pair of fastener tapes;
• a pair of fastener element rows respectively including a plurality of fastener elements arranged in a tape longitudinal direction along opposing tape-side edge portions of the pair of fastener tapes, and coupling yarns coupling the plurality of fastener elements which are adjacent to each other in the tape longitudinal direction, the fastener element rows respectively sewn to the tape-side edge portions;
• and
• a slider configured to engage and disengage the pair of fastener element rows,
• wherein each of the fastener elements includes:
• a body portion sewn to the fastener tape;
• a neck portion extending from the body portion in a tape width direction and in a direction toward an opposite fastener tape, and constricted in the tape longitudinal direction;
• an engaging head portion further extending from a tip end portion of the neck portion in the tape width direction and in a direction toward the opposite fastener tape and swelling up in the tape longitudinal direction, the engaging head portion being engageable with opposite fastener elements;
• and
• a pair of shoulder portions provided at both sides of the neck portion in the tape longitudinal direction, and configured to come in contact with opposite engaging head portions in an engaging state, and
• wherein the pair of fastener tapes have stretchability in the tape longitudinal direction.