To eliminate loss time in transfer operation of yarn winders by providing a carriage which transfers and conveys thread winders with a surface treatment apparatus of conducting surface treatment such as stripping yarns on the surface of the yarn winders, and conducting surface treatment for yarn winders on the carriage while conveying the yarn winders on the carriage.

A winder 100 is provided with two bobbins 2 mounted in series respectively on respective bobbin holder so as to wind two packages P at a time. A carriage 200 equipped with wheels 41 under the platform of the carriage, facing the winder 100, is provided so as to move freely between the winder 100 and a product storage place. The carriage 200 is provided with a plurality of yarn guides 44 and brushes 46 corresponding to respective packages P and a plurality of suction nozzles 47 corresponding to the bunch winding B of the package P for the surface treatment apparatus at a position separated from a bobbin supporting spindle 42 in the radial direction and respective suction nozzle is connected with a negative pressure source through a yarn scrap box 49 with a duct 48.