To provide a method and a device for continuously feeding a packing string to a binding device when binding a box-shaped baggage.

A center shaft of a first reel 2a with a first packing string 1a wound therearound in a cylindrical shape is horizontally retained, and rotatably supported to form a knot on an inner end of the first packing string 1a. An outer end of the first packing string 1a is attached to a pinch roll 9 from a knot detector 7 via a packing string coupler 8. While the first packing string 1a is fed to a binding device by the driving force of the pinch roll 9, an outer end of a second packing string 1b attached to the packing string coupler 8 in advance is tied to the first packing string 1a when the knot detector 7 detects the knot. Then, the knot of the inner end of the first packing string 1a is coupled to the knot formed on the outer end of the second packing string 1b.