To provide a bobbin processing part of an automatic winder for preventing the degradation of operating efficiency resulting from the entanglement of yarns by making yarns sagging from a bobbin and yarn waste hard to entangle.

The bobbin processing part 103 of the automatic winder 101 comprises a round belt 115 as a first conveyor belt arranged along a carrying passage for a tray 182 of the bobbin 180 for carrying the tray 182, and a second conveyor belt arranged parallel to the round belt 115 in part of the carrying passage for carrying the tray 182 together with the round belt 115. The second conveyor belt is a flat belt 121 (an angular belt 141).