a presser foot 36 is rotatably secured to the bracket by a shaft 37 the presser foot 36 has a feeler 34 and a drop wire 35 the tip of the feeler 34 is caused to lightly contact the twisted yarn yc so that the feeler is prevented from rotating when the second cutter 32 cuts a yarn any yarn ceases to exist at the contact position whereby the feeler is unlocked the presser foot 36 then rotates in the counterclockwise direction as viewed in the drawing by its own weight until the drop wire 35 abuts against the top of the tenser 2 and stops as indicated by the phantome lines in fig2 at this time the tip of the drop wire presses the first yarn component ya so that the yarn ya is no longer taken out from the package pa when the first yarn component ya or the second yarn component yb is broken in the aforementioned twister during twisting operation the yarn breakage detecting device 14 detects it simultaneously with its occurrence and operates the first cutter 31 and the second cutter 32 to cut the first yarn component ya and the second yarn component yb in case where the first yarn component ya is broken the first cutter 31 is operated to cut the running second yarn component yb then after a lapse of 0 5 to 3 0 seconds the second cutter 32 is operated the piece of the yarn which is produced on the first yarn component ya winding side by the yarn breakage passes across the second cutter 32 during a period beginning with the occurrence of the yarn breakage and ending with the actuation of the second cutter 32 at this time the piece of the yarn which is produced.