Slide fastener

A slide fastener including:

• a pair of left and right fastener tapes;
• and
• a plurality of synthetic resin fastener elements lined along opposing tape side edge portions of the fastener tapes, wherein
• each fastener element includes an upper half element portion disposed at a first surface side of the fastener tape and a lower half element portion disposed at a second surface side of the fastener tape,
• the upper half element portion includes a first tape-sandwiching portion having a predetermined dimension in a tape length direction, and a first head portion of a tapered form that extends from the first tape-sandwiching portion toward an outside of the tape up to a forefront of the lower half element portion and has a dimension in the tape length direction that gradually decreases toward the forefront of the lower half element portion,
• the lower half element portion includes a second tape-sandwiching portion that sandwiches the fastener tape together with the first tape-sandwiching portion, a neck that extends from the second tape-sandwiching portion toward the outside of the tape and has a shape constricted in a front and rear of the tape length direction, and a second head portion that extends from a forefront portion of the neck and bulges in a front and rear of the tape length direction,
• wherein the first head portion includes a thin walled portion in which a height dimension in a vertical direction of the fastener element is smaller than a height dimension of a thin walled start portion set on the upper half element portion and the thin walled portion is disposed from the thin walled start portion to a forefront of the first head portion, and
• the thin walled portion includes a downward inclined surface that is inclined downward to gradually decrease in the height dimension of the fastener element toward the forefront of the first head portion from the thin walled start portion,
• wherein the first head portion includes a first narrow width portion that extends from the first tape sandwiching portion and a second narrow width portion that extends from the first narrow width portion via an inflection portion.