To provide a pipe joint having both high reliability and large flexibility in installation of a pipe to a cooling plate of a wafer chuck.

In this pipe joint, a joint boss 20 has a female taper part 23 and a female screw part 24 thereinside and is fixed to a case 44 of the cooling plate. A piping component 30 has a base part 31 connected to the pipe for supplying and discharging a heating medium, a male taper part 32 corresponding to the female taper part 23, and a floating male screw 33 turnably installed to the base part 31 and screwed in the female screw part 24. By inserting the male taper part 32 into the joint boss 20, screwing the floating male screw 33 into the female screw part 24 and fastening the floating screw 33, the male taper part 32 is pressed to the female taper part 23, and they are closely stuck to each other. As a result, the joint boss 20 and the piping component 30 are sealed from each other and are mechanically fixed to each other.