To provide a roof for a joint part capable of surely preventing outward projection and damaging, by absorbing large swinging motion in the different lateral directions in the joint part.

This roof for the joint part is composed of a rotatable roof plate having one end part pivoted on a pivot shaft in the horizontal direction by a building frame on the joint part side of one building of a part for installing the roof, having an intermediate part of an angle shape pivoted on the pivot shaft in the horizontal direction and having the other end part capable of abutting on the building frame on the joint part side of the other building, at least one or more of always extensively energized expandable supports having one end part installed in the building frame on the joint part side of one building of a lower position of this roof plate and attached with the other end part of the roof plate, and a stopper mechanism arranged so that the other end part of the roof plate abuts on the building frame on the joint part side of the other building.