To prevent the leakage of fluids caused by the bending, turning-up or cutting of a resin tube generated by vibration, bending or the like.

A joint is composed of a joint main body l and a nut 2, and the joint main body 1 is provided with, in one end, a male screw part and a cylindrical part smaller in diameter than the male screw toward a tip. In the outer peripheral wall of the cylindrical part, a rear guiding part and a front guiding part are formed toward the tip, and in the inner peripheral wall of the nut 2, a female screw part engaged with the male screw part of the joint main body 1 and a nut guiding part smaller in diameter than the female screw part are formed. Then, a gap between the inner diameter of the nut guiding part of the nut 2 and the outer diameter part of the front guiding part of the main body joint is set to be smaller than the thickness of a resin tube 3.