An adjustable shelving assembly includes four corner members of L-shaped cross section, either half of each corner member comprising aperture members each including an upper, larger circle and a lower, smaller, vertical hole overlapping the larger circle thereof; at least one group of four interconnecting members each comprising upper and lower aperture elements and a through hole besides each of the upper and lower aperture elements for positioning the interconnecting member, each aperture element comprising an upper, smaller, vertical hole and a lower, larger circle overlapping the vertical hole thereof; retainers each for fastening the corner member and the interconnecting member; and lock pins each comprising a head including a cut, and a shaft having ridges. The lock pin is fastened in the larger circle of the aperture member and the through hole. The cut is fastened in the larger circle of the aperture member.