A switching mechanism is provided for switching the position of a yarn feeding mouth to another and swinging a yarn feeder. The switching mechanism includes a push operating portion for changing a swing direction of the yarn feeding mouth and a height position thereof in cooperation with a leading means until a yarn feeder selected by the leading means feeds a yarn and is led from a stopped state. The push operating portion forms a lowering surface in a surface of the push operating portion. The lowering surface is used to further lower the yarn feeding mouth from a yarn feeding position so as to allow the yarn to pass under a backface side of the needle.