PURPOSE: To ensure a heating action to be easily and safely kept, and a pipe joint of thermal contraction type shape memory alloy to be heated for contraction by laying an oxidized heating composition on the external surface of the joint in sealed state, and bringing the composition in contact with the air when necessary.

CONSTITUTION: A pipe joint 1 is constituted of a joint body 10 made of thermal contraction type shape memory alloy molded in the form of a sleeve, and a sealed housing section 13 laid on the external surface of the body 10. Also, the sealed housing section 13 is constituted of a cylindrical housing vessel 13a having vent holes 130 and a housing cap 13b to close the holes 130. Furthermore, the holes 130 are sealed with a metal adhesive tape 15 and the vessel 13 houses a cylindrical gauze 16. Then, space inside the gauze 16 is filled with an oxidized heating composition 17 in such a way that the layer of the fine powder body 17b of the composition 17 comes inside and the layer of a coarse powder body 17a comes outside. According to this construction, the composition 17 is kept in contact with the air for heat generation, thereby heating the joint body 10 and causing the contraction thereof for tightening a plurality of pipes 2 and 3.