To improve the usability of thread winders by gethering together in a compact form the pneumatic piping of their rocking pivotable cradle arm compact.

The thread winder comprises a cradle arm 4 rockable around a cradle shaft 13, bobbin holders 5 mounted on the cradle arm 4, compressed-air- operated operation tool for detachably operating holders 6 of the bobbin holders 5, and pneumatic piping 17 for feeding compressed air to the operating tool. The rocking centers C of the cradle arm 4 and pneumatic piping 17 are coincided with each other. For structural simplification of the pneumatic piping 17, the cradle shaft 13 may be hollow to simply that portion of the pneumatic piping 17 which corresponds to a portion of the rocking center C thereof. For smooth torsion of the rocking center portion of the pneumatic piping 17 during rocking movement, the hollow cradle shaft 13 may be immovable and the pneumatic piping 17 may join, at its swingable portions 17c, to the cradle shaft 13 via rotary joints 15.