PURPOSE: To fusion-connect without using a clamp device, facilitate production, and eliminate the possibility of leakage even if any crack is produced at the connected part of a connection pipe by providing a stopper member, which locks it on the inner peripheral surface of the open end part of a thermoplastic resin pipe inserted into a pipe socket, at the inner peripheral part of the pipe socket.

CONSTITUTION: The joint body 10 of an electric fusion joint is formed with thermoplastic resin such as polybutylene, polyethylene etc. Also heating wire 20 is wound in the inner peripheral part of the joint body 10, and both ends of the heating wire 20 are connected to terminals 21 and 22. Then an annular stopper 14 projected to the inner peripheral side so as to control the inserting amount of a resin pipe 40 is provided at the bottom side of the pipe support port 11 of the joint body 10, and a stopper member 30 is installed at the inner peripheral end of the stopper 14. In addition, the stopper member 30 is formed in a cylindrical shape in which serration locking part 31 to lock it by inserting it into the inner peripheral surface of the resin pipe 40 on the outer peripheral surface of its both end parts, and a fitting groove 32 is provided at the center part to lock it at the inner peripheral end of the stopper 14.