Abstract: The present invention relates to a support structure for shelves suitable for ready changing of the height and the relative distance between individual shelf boards.The support structure consists of vertical members adapted to be fastened to another vertical structure and of brackets adapted to be moved along the vertical members and to be held therein by frictional locking forces. Each vertical member has a uniform cross section in the shape of a rectangular, assymetrical channel comprising a web, a base flange provided with means for attaching it adjacent to a wall and an outer smaller-width flange provided along its outer with a re-entrant first guide parallel to the plane of the web. Inside the base flange is provided a second guide ridge, which faces the first guide ridge, but at a greater distance from the web than the first guide ridge.