To miniaturize a knotting device having a plurality of yarn to be knotted, arranged in advance.

A yarn selecting device 30 for holding the yarn 1 by respective plural yarn holding parts 32 laterally arranged in a line, and successively supplying the yarn, is mounted on a guide rail 22 movably among a supplying position A as a knotting work part, a position opposite to a knotting position B, and a retracting position (left in Fig. 3) separated from the position opposite to the position B to a side part, the driving force of a first driving motor 39 is transmitted to a rack formed on a lower end of a machine frame 31 of the yarn selecting device 30 for selectively moving the yarn selecting device 30.