Abstract: Set of structural elements for producing supporting structures, having supporting bars 5 and cylindrical connecting elements 1 for insertion heads 6 provided on the end sides of the supporting bars 5, the connecting elements being provided with a plurality of slots which are open on one side and extend, parallel to one another and to the axis of the cylindrical connecting elements, from the surface to the center, and the slots each being widened, at a distance from the radial ends of the same, to form chambers for receiving the insertion heads. The insertion heads are formed in the flat end regions of the supporting bars, at a distance from the end edges, in that at least two parallel slits are provided at an angle of 90.degree.