A housing frame includes a first and second beams connected to each other through a connection member. The two beams are each obtained by perpendicularly bending a metal plate twice in the longitudinal direction. The second beam is arranged perpendicular to the first beam. The connection member has a connection base portion extending from a bent side surface of a second base portion to a bent side surface of a first base portion through a cut portion formed in a first side portion and overlaps with the first base portion and the second base portion. The connection base portion and the first base portion are fastened together by a first fastening member, and the connection base portion and the second base portion are fastened together by a second fastening member.