An assemblable and disassemblable container is disclosed wherein a short wall member includes upper corner reinforcing members each formed at a corresponding corner formed by an upper horizontal flange and an endwise vertical side plate portion of the short wall member, and the upper corner reinforcing member includes an inclined coupling rib coupling the vicinity of the end of the upper horizontal flange to the vicinity of the upper end of the endwise vertical side plate portion, and wherein the lower end of the inclined coupling rib is positioned close to an endwise vertical side plate portion side of a lower horizontal rib of a horizontal portion included in a fitting block member. This configuration allows the short wall members and thus the container formed into a box shape to be increased in strength and rigidity, and can be prevented from undergoing torsional deformation.