A housing includes: a housing body that contains at least one electromechanical or mechanical component, the housing body including a front plate and a pair of side plates, the plates being connected to a bottom plate in such a manner that the housing body includes an opening; a cover for closing the opening; and a gasket interposed between an edge portion of the housing body and an edge portion of the cover to tightly close an inside of the housing body. An edge portion of each of the side plates has a curved shape.