PURPOSE: To construct a structure with greater strength using a thin sheet metal by constructing a cabinet body by positioning, welding, and fixing a ceiling plate and a bottom plate where a bag bending part is formed by bending four sides of each of the ceiling plate and the bottom plate such that each of them has a greater joint area with respect to a side plate provided with a reinforcing member.

CONSTITUTION: A body structure is constructed by integrally welding and fixing a bottom plate 1, a ceiling plate 2, and a pair of right and left side plates 3. The side plate 3 includes a U-shaped cross section channel part B formed by folding back a front and back sides in predetermined widths along the height thereof, and includes a reinforcing plate 7 having a U-shaped cross section along the height of the side plate, and being fixed at the center of the internal surface thereof. For assembling the members 1, 2, 3, the ceiling plate 2 and the bottom plate 1 are held by opposite side plates 3, and the lower or upper surface of bag bending part A of the ceiling plate 2 and the bottom plate 1 is supported on the end surface of the channel part B. Further, the side surface of the bag bending part A is positioned such that it makes contact with the upper and lower regions of the internal surface of the side plate 3, and the contact region is welded and fixed.