A stretch yarn includes a multifilament including fibers having a coiled crimping form in a fiber axial direction, wherein a coil diameter distribution of crimping in the fiber has two or more groups, a ratio of a maximum group average value to a minimum group average value of the coil diameter (a maximum group average value/a minimum group average value) is less than 3.00, and a cross section of the fibers constituting the multifilament is an eccentric core-sheath cross section.

A false-twisted low-fused polyester yarn has a non-untwisted part having a twist in a false-twist direction, an over-untwisted part having a twist in a direction opposite to the false-twist direction, and a non-twisted crimped part having no twist, alternately disposed along the longitudinal direction of the yarn, the average length of the non-untwisted part being no more than 7 mm, the average length of the over-untwisted part being at least 7 mm, and the degree of fusion-bonding in the yarn longitudinal direction being no more than 50%.