To improve productivity of a switching cock by reducing occurrence of mismatching due to irregularities on a sliding face of a mobile shaft of the switching cock during cutting.

A truncated cone-shaped mounting hole 16 leading to a plurality of air passages 17 is formed in a cock body 10, and a mobile shaft 20 having a plurality of ventilation passage 24 for switching the air passage 17 is basically formed of a cylinder 21 whose outer diameter is smaller than the small diameter section of the truncated cone-shaped mounting hole, and whose length is almost the same as that of the mounting hole. The axial center section of a cylinder 21 is configured in a shorter taper axial part 23 whose outer diameter is larger than that of the cylinder, and whose outer circumferential face 22 can be fit into the axial center section of the mounting hole 16, and all the ventilation passage 24 leading to the air passage 17 are arranged in the taper axial section 23.