PURPOSE: To prevent the rotation impossibility of a rotary fiber binder by flowing water from a depression disposed on the pulley portion of a rotator toward a threading pipe and allowing the water to fall through flow holes disposed in the depression of the pulley.

CONSTITUTION: A threading pipe 2 for passing a delivered fiber is inserted into a rotator 2. Flow holes 9 are disposed in a depression disposed on the pulley 3 and water is flown down toward the groove of the pulley 3. A water- passing hole 11 is disposed in a fitting 7 and water is flown out from a water- flowing pipe 12 toward the water-passing pipe 11. The water is penetrated between the threading pipe 1 and the rotator 2.