PURPOSE: To untwist, unravel and open up the yarn by arranging the free end of the yarn in the specific compressed air flow that is introduced into the channel and applying tension to the yarn.

CONSTITUTION: The free end of the yarn is held at the upstream section of the compressed air flow to be introduced into the channel and positioned with the notch 7. The free ends of the yarn extends toward the downstream side. The air jet generator 4 is set so that a jet stream is alternately intercepted with the frequency of several hundred Hz order toward the axis in the longitudinal direction of the channel element. The free end of the yarn is vibrated in the same frequency of the air flow, twisted and the loading and unloading of tension are repeated every time the vibration.