A shelf structure comprising: - a plurality of uprights in the form of tubular elements, each having an upright wall with an inner surface, - a multiplicity of crosspieces (5; 52; 53; 54) perpendicular to the uprights in the form of tubular elements, each crosspiece (5; 52; 53; 54) having a crosspiece wall with an inner surface, - a multiplicity of cylindrical junction pins, singularly having a maximum diameter cylindrical surface and, at a first end, a portion having a diameter reduced with respect to said maximum diameter cylindrical surface and being provided with an external threading, and, between said first end and a second end, a circumferential groove, - a threaded dowel intended to be received in the circumferential groove of the cylindrical junction pin, characterized in that the shelf structure further comprises: - each upright provided with at least one through bore in its upright wall; - an internally threaded bush suitable for engaging said external threading of the cylindrical junction pin, the bush having a bottom and being provided with a bore in its bottom; and - a self-tapping screw passing through said bore formed in the bottom of the bush and being adapted to tap the through bore in the upright wall; each crosspiece (5; 52; 53; 54) being provided in its crosspiece wall with at least one threaded through bore; each cylindrical junction pin being able to be inserted in a crosspiece so that its cylindrical surface is in tangential contact with the inner surface of the crosspiece wall; and the threaded dowel being intended to be screwed into the at least one threaded through bore of the crosspiece (5; 52; 53; 54) and to be received in the circumferential groove of the cylindrical junction pin inside the crosspiece (5; 52; 53; 54), so as to connect the crosspiece (5; 52; 53; 54) to the cylindrical junction pin. - a plurality of uprights in the form of tubular elements, each having an upright wall with an inner surface, - a multiplicity of crosspieces (5; 52; 53; 54) perpendicular to the uprights in the form of tubular elements, each crosspiece (5; 52; 53; 54) having a crosspiece wall with an inner surface, - a multiplicity of cylindrical junction pins, singularly having a maximum diameter cylindrical surface and, at a first end, a portion having a diameter reduced with respect to said maximum diameter cylindrical surface and being provided with an external threading, and, between said first end and a second end, a circumferential groove, - a threaded dowel intended to be received in the circumferential groove of the cylindrical junction pin, characterized in that the shelf structure further comprises: - each upright provided with at least one through bore in its upright wall; - an internally threaded bush suitable for engaging said external threading of the cylindrical junction pin, the bush having a bottom and being provided with a bore in its bottom; and - a self-tapping screw passing through said bore formed in the bottom of the bush and being adapted to tap the through bore in the upright wall; - each upright provided with at least one through bore in its upright wall; - an internally threaded bush suitable for engaging said external threading of the cylindrical junction pin, the bush having a bottom and being provided with a bore in its bottom; and - a self-tapping screw passing through said bore formed in the bottom of the bush and being adapted to tap the through bore in the upright wall; each crosspiece (5; 52; 53; 54) being provided in its crosspiece wall with at least one threaded through bore; each cylindrical junction pin being able to be inserted in a crosspiece so that its cylindrical surface is in tangential contact with the inner surface of the crosspiece wall; and the threaded dowel being intended to be screwed into the at least one threaded through bore of the crosspiece (5; 52; 53; 54) and to be received in the circumferential groove of the cylindrical junction pin inside the crosspiece (5; 52; 53; 54), so as to connect the crosspiece (5; 52; 53; 54) to the cylindrical junction pin.