Pipe joint unit and method of manufacturing the same

A pipe joint unit comprising:

• a first pipe member including a male joint that has an outer peripheral surface;
• a second pipe member including a female joint that has an inner peripheral surface, the second pipe member coupled to the first pipe member such that the male joint is received in the female joint and the outer peripheral surface of the male joint is opposed to the inner peripheral surface of the female joint;
• and
• a pipe joint member including an engagement part that is elastically movable in a radial direction, and engaged with the first pipe member and the second pipe member, wherein
• the male joint and the female joint include rotation restricting parts on the outer peripheral surface and the inner peripheral surface, respectively, and
• the rotation restricting parts are configured to restrict relative rotation of the first and second pipe members.