Bulky yarn

A bulky yarn made of synthetic fibers, comprising:

• a sheath yarn;
• and
• a core yarn twisted with the sheath yarn to fix the sheath yarn,
• wherein the sheath yarn has a spiral structure with a radius of curvature of 2 mm to 30 mm;
• by 10 sites randomly selected from the single bulky yarn consisting of the sheath yarn and the core yarn, and the textured yarn is photographed at a magnification at which 10 or more sections from a twist point between the core yarn and the sheath yarn to the next twist point (that is, each section is one loop) can be recognized in the longitudinal direction of the textured yarn, and observed for the determination each of the 10 photographed images, the number of breaking points of the sheath yarn per 1 mm of the bulky yarn was counted for 10 loops, and the average of the number of breaking points of the loops was calculated, and the average was rounded off to the first decimal place to give the number of breaking points of the loops (number/mm), and the number of breaking points on average of the total of 100 loops is 0.2/mm or less.