An adjustable shelving assembly is provided with four corner members of L-shaped cross section, either half of each corner member including 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 including upper and lower aperture elements and a through hole between the aperture elements, each aperture element including an upper, smaller, vertical hole and a lower, larger circle overlapping the vertical hole thereof; elongated retainers each including two enlargements at both ends respectively, an annular groove adjacent to one enlargement, and an annular shoulder between the groove and the other enlargement; lock pins each having a substantial portion fastened in the larger circle of the aperture member and the through hole; and at least one flat shelf each anchored on tops of the interconnecting members.