PURPOSE: To prevent mixing of air into a pipe by mounting a seal member into a cylindrical member of a pair of pipe joint half parts, connected to the pipe, and connecting the seal members to each other in an opening side, where the two cylindrical members are opposed, when the pipe joint half parts are connected.

CONSTITUTION: A cylindrical member 62 of one pipe joint half part 60, connected to one pipe, is formed. While a cylindrical member 102 of the other pipe joint half part 100, connected to the other pipe, is formed. A seal member 64 is liquid- tightly slidably mounted into the cylindrical member 62. Similarly a seal member 104 is mounted into the cylindrical member 102. The seal members 64, 104 are connected to each other in an opening where the two cylindrical members 62, 102 are opposed, with these seal members serving as a pressure transmitting member. As a result, the necessity for air bleed work, after the pipe or the like is built in a car body can be eliminated.