To provide a relay joint reducing the size, simplifying mounting work and sufficiently usable even in an environment to which vibration is transmitted.

In the relay joint 10, cylindrical bodies 12, 14 are arranged on the outdoor side of a storage body 130b, and cylindrical bodies 13, 15 are arranged on the indoor side of the storage body 130b. In this layout, the relay joint 10 is fixed to a boss part 130c of the storage body 130b. At this time, a boss BS formed on a plate-shaped body 11 is fitted into an opening part HL, and then the relay joint 10 is fixed by bolts BT. Since a plurality of communication bodies are formed in the relay joint 10, it is not required to mount a large number of relay joints, thus reducing the number of components mounted to the storage body 130a. Moreover, since fixing means 16 are provided in the relay joint 10, the plurality of communication bodies are fixed to predetermined places by once fixation work, reducing complicated work for fastening a fixation tool.