The shelf bases are fixed on wooden support columns (2) by holders (6) which have support arms which engage laterally round the columns and are connected together by a cross support. The support arms have two or more vertically spaced support angles (8,9) set in planes at right angles to the front face (10) of the columns. In the holding position where the shelf bases are held horizontally protruding and can be displaced in the holders by tilted sliding along the columns the lower support angle is supported on the front face of the column and the upper support angle (9) is supported on a rear bearing face (11). The internal spacing of the facing edges of the support angles on a support arm is greater than the spacing of their off-set planes
