The present invention provides a transverse device and a yarn winder with the same. A cam mechanism (37) causes a traverse yarn guider (19) to perform linear reciprocation along a traverse direction. A supporting part (42) supports the cam mechanism (37) (and a cam box (32) for accommodating the cam mechanism (37)) in a manner that relative movement along the traverse direction relative to a base part (33) is allowed and relative movement along a direction that is orthogonal with the traverse direction is inhibited. A spring (50) absorbs impact of the cam mechanism (37) in the traverse direction.