To perform strong fitting without leaving any spaces by forming the axial direction sectional shapes of a fitting groove and an inner peripheral end to be trapezoidal to be coincident with each other in a structure where a metallic socket loaded around a hose is pressed in a centripetal direction and the inner peripheral end of a flange part and the fitting groove of a nipple part with each other.

An engaging groove 21 and a fitting groove 22 are formed by rolling in the outer periphery of a nipple part 2 inserted into a flexible rubber hose 3 in one end of a metallic tube 1, and for caulking a socket 4, the hose 3 is buried in the engaging groove 21 and the flange part 42 of the socket 4 is fitted in the engaging groove 22. In this case, the fitting groove 22 of the nipple part 2 and the inner peripheral end part 43 of a disk-like flange part 42 of the socket 4 engaged with the same are formed to be trapezoidal in axial direction section. When such a socket 4 is loaded and caulked in a centripetal direction, the inner peripheral end part 43 of the flange part 42 of the socket 4 is bitten and engaged with the fitting groove 22 and thus the socket 4 and the tube 1 are fixed.