To connect a pipe and a hose through the pipe to a compressor surely and by reducing a cost.

In a first pipe 30, an insertion tip end part 31 inserted in a pipe mounting hole 11 successively in one end side, annular swollen part 32 extended outward in a diametric direction, and non-circular part 34 having a pair of mutually opposed parallel wall parts behind this swollen part, are mechanically formed integrally with a tube. The first pipe 30 is slid in the notched part by inserting the non-circular part 34 to a notched part 25 of a mounting plate 20, to be mounted in the mounting plate incapable or rotating and moving in an axial direction. In the first pipe 30, by mechanically forming the swollen part and non-circular part 34 integrally with the tube, a cost is reduced as compared with that using a forging material in the part, and necessity for also cutting work for surface finish is eliminated.