To provide a traversing device for thread winder, capable of preventing winding a thread (y) into the device inside, even a traverse guide is moved in a counter-traverse direction at the time of notching or the like.

In this traversing device T for a thread winder equipped with traverse guides b1 and u1 for running in reverse directions with each other, and alternately engaging a thread (y) to traverse the thread (y); an entangling preventing means is provided which is preventing the entangling of the thread (y) into the device inside by the traverse guides b1 and u1 when the traverse guides b1 and u1 are moved to counter-traverse directions bwr and uwr.