Abstract: To provide a method and device with which Alternate Twisted Yarn can be produced simply and inexpensively. An Alternate Twisted Yarn is produced by alternately repeating with a neutral and tilt switching method and twisting yarn 1 in the reverse direction on both sides of pulley 2 driven by yarn 1 that is inserted between the flanges of pulley 2, so that the yarn passage is bent or flexed. Shaft 3 of this pulley 2 is inclined to the yarn 1 yarn passage plane to bring yarn 1 into contact with the flange section 2a's internal surface of pulley 2, and in the neutral position under which yarn 1 is not twisted on both sides of pulley 2, with shaft 3 of pulley 2 being made perpendicular to the yarn 1 yarn passage plane to cut off its contact to the pulley 2 flange section 2a's internal surface.