PURPOSE: To surely separate paralleled two-ply yarn into single yarns so as to end the two ply yarn by single yarn each by moving clampers backward to separate the strongly clamped yarn from the other yarn, and moving yarn guide clampers.

CONSTITUTION: Clampers 9, 9a adapted to open and close like a pair of scissors are moved forward in an open state to two paralleled yarns 36, 37, and after the paralleled yarns 36, 37 are positioned in an opening of the clampers 9, 9a, the opening is closed so that the yarn positioned in the inner part of the opening is clamped more strongly than the other yarn. The more strongly clamped yarn is still clamped and separated from the other yarn by moving the clampers 9, 9a backward, and yarn guide clampers 27 are moved onto a backward locus of a clamp portion of the clampers 9, 9a.