To easily provide a pipe joint having a branch part joined and assembled by welding or the like so as to be reinforced and its reinforcing structure.

This pipe joint main body 12 is composed of a main pipe 13 made of a polyvinyl chloride resin and a junction pipe 14, which are adhered to each other by welding or the like so as to be integral. In this case, a reinforcing layer 15 for covering the outer peripheral surface of the welding joined part of the pipe joint main body 12 and a leg part 21 protruded from a part of the outer peripheral surface are made of reaction injection molding materials using norbornene type monomar such as dicyclopentadiene and a metathesis catalyst as main materials.