A fluid joint having a first coupler includes a cylindrical first main body and an outer cylinder located at the outer circumferential side of the first main body, which protrudes to a distal end of the first main body, and is provided with a first engagement portion and a second engagement portion at the distal end. The second coupler includes a second main body provided with a third engagement portion that can engage with the first engagement portion and a fourth engagement portion that can engage with the second engagement portion. The phases of the first engagement portion and the third engagement portion match in the process of engagement thereof, so that the second engagement portion and the fourth engagement portion engage with each other to join the outer cylinder and the second main body together.