To prevent the noise and the cutting of thread by the vibration by surely applying the torque of a bobbin from the start of winding to the stable area.

An electromagnet 10 is worked when a foot switch is pedalled, and a bobbin which strongly pulls a swing arm 7 is firmly kept into contact with a drive roller. When the thread is wound on the bobbin and the winding diameter is thickened, the swing arm 7 is separated from the drive roller. On this occasion, a permanent magnet 13 is worked together with the swing arm 7, a shaft 15 is slided, a spring 16 is compressed, and the bobbin is pressed and kept into contact with the drive roller by the force of the compressed spring and the ordinary bearing. When the winding thickness is further increased, a gap A between a stopper 21 and a spring fixing nut 18 is filled up, the permanent magnet 13 is not slided more, and finally the bobbin is closely kept into contact with the drive roller by the attraction force of the permanent magnet 13. Then the permanent magnet 13 is released from the swing arm 7, and the thread is wound only by the ordinary bearing pressure.