To obtain even load capacity without using a double steel pipe unlike before to impart an expansion/contraction property for setting an ideal width to a storage shelf used in a closet or the like, and to provide a commodity having the same value by a material not using steel in the surface not to cause anxiety about generation of a problem such as rust in use of a steel pipe.

Instead of an expansion/contraction system by a conventional double structure of the steel pipe, a system wherein expansion and contraction are executed by moving a shelf plate on slide bars is adopted. By using a resin in the slide bar for moving the shelf plate, an unexpected accident caused by the rust or the like is prevented.