Abstract: A pipe joint device includes a nut defining a threaded hole and including an inward flange that defines a through hole and that has a shoulder surface facing the threaded hole, a tube body having inner and outer end portions, and a stopper detachably sleeved on the tube body. The inner end portion extends through the through hole, has an inner end surface and an outer peripheral surface connected to the inner end surface and formed with an external thread. The stopper has opposite first and second abutment surfaces and an inner surface formed with an internal thread threadedly engaging the external thread. The inner end portion further extends through the stopper, such that the second abutment surface faces and abuts against the annular shoulder and the first abutment surface is disposed not farther away from the outer end portion than the inner end surface.