PURPOSE: To improve the efficiency of doffing operation, by providing a paper tube-transfer conveyor along each spindle of a spinning frame and providing a seed yarn-winding means to a doffing apparatus moving along each spindle.

CONSTITUTION: A mobile truck 4 movable along a number of spinning spindles attached to a spinning frame is provided with a doffing means, an ending means and a means for winding a seed yarn on a paper tube. A belt conveyor 21 to transfer a paper tube 22 is placed along each spinning spindle. When a spinning spindle among a number of spinning spindles is fully wound and the full- bobbin signal is transmitted, the mobile truck 4 is moved to the position of the spindle and the conveyor 21 is energized to transfer the paper tube 22. After the doffing operation by the doffing means of the truck 4, a paper tube wound with a seed yarn 32 by a seed yarn-winding means is supplied to the winding means of said spindle. The seed yarn is tied with a yarn delivered from a drafting part by an ending means. The seed yarn-winding means receives the paper tube 22 transported by the conveyor 21 and winds a seed yarn on the paper tube.