PURPOSE: A cover is fitted to the open end of the hollow shaft in a double- twisting type spinning frame to prevent the air from running into the guide hole by following the rotation of the hollow shaft, thus increasing the twisting efficiency on the yarn.

CONSTITUTION: In a double-twisting spinning frame where the yarn Ya running out of the drafting machine is made to advance in the reverse direction from the side guide equipped with false-twisting nozzle 40 through the hollow shaft 6 which is rotating at a high speed, then to run out of the hole 6c and wound up around the stationary winder, a cover 20 is fitted to the open end of the hollow shaft 6 to prevent the air from running into the guide hole by the rotation of the hollow shaft 6. The cover may be a sphere or disk. Thus, the twisting efficiency by the false-twisting nozzle is increased, since the air is prevented from flowing into the shaft 6 from the opening.