FLUID COUPLING

PROBLEM TO BE SOLVED: To provide a fluid coupling that prevents a pipe from being detached by maintaining the engagement of a ratchet and a pipe with a simple structure and reduces energy loss by reducing pressure loss.SOLUTION: The fluid coupling 11 includes: a socket 12 having an insertion hole 12a extending from a first end 12b to a second end 12c opposite thereto; an adapter 14 mounted to the first end 12b of the insertion hole 12a, which has a through-hole and is connected to a first pipe 31; a holder 35 having a sealing member 41 at the side of the second end 12c, which is biased from the first end 12b toward the second end 12c and has a through-hole; a holding member 17 rotatably provided at the second end 12c of the socket 12 for locking and holding an outer circumferential surface of a second pipe 16; and an elastic member 18 for pressing the holding member 17. A preventing member 23 for preventing the rotation of the holding member 17 is arranged within the rotational locus of the holding member 17.