A tube assembling device consisting of hub-carriers and hubs for erecting three-dimensional structures. The hub-carriers consist of two pairs of half-rings, bearing tongues offset by 90.degree. along an antero-posterior axis and linked by four connecting lugs, they support radial hook-shaped expansions. The hub-carriers can link two tubes in a fixed or balanced position, can be fixed at the tube end, can be fixed along a tube and support hubs. The hubs support tongues are positioned folded or unfolded inside the tubes used for the construction of the radial expansions into rings and catching teeth internal to the rings. The assembly enables the hubs and hub-carriers to be linked by tubes or elastic links and constitute by folding or combining the hubs and hub-carriers nodes for modelling structures of numerous types from a reduced number or elements.