To keep the tension of weft yarns of an air blow weaving machine and reduce the air consumption and the amount of residual yarns in the discharging of the weft yarn ends.

This weft tensioning device blows and bends the front end of an air blow-inserted weft yarn into a direction almost perpendicular to the running direction of the weft yarn, and keeps the tension of the weft yarn before beating. The device is provided with a yarn holding finger 14 placed between the blow-bending position of the weft yarn end and the weaving end, and a driving magnet placed on a longitudinally stable position along the motion loci of a reed which drives to open and close the yarn holding finger 14. When weft insertion is completed, the yarn holding finger holds the weft yarn and at the same time the air blow is stopped. Since the weft yarn directly after the weft insertion is held in a state where the end of the weft yarn is blown to bend and its swing is suppressed, the air blow for bending the weft yarn end is not needed thereafter.