To provide an electrofusion joint capable of efficiently cooling a fusion part between a joint body and a pipe member inserted into the joint body, even when the thickness of the joint body is thick.

This cylindrical joint body 12 for inserting the pipe member 11 is formed with a flow passage 24 for passing a refrigerant 23 for cooling the fusion part for solidifying the fusion part 22 between the mutually fused joint body 12 and pipe member 11, by respectively fusing an inner peripheral part 12c of the joint body 12 and an outer peripheral part 11b of the pipe member 11 by a heating element arranged in the inner peripheral part 12c of the joint body.