PURPOSE: To obtain the subject apparatus effective for simplifying the threading operation by opening a fluid-ejection hole on a yarn-passing hole perpendicular to the yarn and forming a yarn-guide hole and a compressed fluid discharging hole at both ends of the yarn-passing hole in respective specific states.

CONSTITUTION: An ejection hole 3 of a compressed fluid is opened on a yarn- passing hole 2 having a circular or elliptic cross section. Yarn guide holes 4,5 are opened at both ends of the yarn-passing hole. The length of the guide hole is ≥5mm and the cross-sectional area of the hole is ≤0.33 times that of the yarn-passing hole. The discharging holes 8,9 opened at both ends of the yarn-passing hole have a total cross-sectional area larger than 1/3 of the cross-sectional area of the ejection hole.