Device for assembly of landing gear on an aircraft structure. The device comprises two segments (14a, 14b) of the shaft aligned along the same center line and fixed to a fitting of the landing gear, two support devices (10a, 10b) fixed to the aircraft structure, two ball joint balls (12a, 12b) installed between the corresponding shaft segments and the support devices and a tension bar (24) connecting the two support devices. One (10a) of the two support devices, preferably turned towards the outside of the aircraft, is deformable by bending or articulation. Advantageously, the tension bar bears on the bearing balls (20a, 20b) and the guide rings are placed between the bar and the shaft segments, to prevent vibrations.