PURPOSE: To efficiently transfer a foil yarn without causing reversion of the right and back sides or breakage by subjecting a moving unit to piston action, transferring the foil yarn between stretched warp yarns under tension and pressing the foil yarn to the side of downward warp yarns in a pressing part of the moving unit in returning.

CONSTITUTION: A moving unit 12 is subjected to piston action along a framelike guide plate so as to enable rising and sinking. Thereby, a foil yarn 3 is transferred between warp yarns (29a) and (29b) under a moderate tension. The moving unit in returning presses the foil yarn just after the transfer to the side of the downward warp yarns (29a) in a pressing part 27 provided near the front edge wall of a chuck mechanism. As a result, the foil yarn is prevented from irregularly floating.