An aircraft undercarriage comprising two rocker beams (1, 2) carrying wheels and mounted to pivot on a common pivot (Y1), the undercarriage including a shock-absorber device comprising two connecting rods (5, 6), each rod (5, 6) being coupled to a respective rocker beam, at least one connecting rod being telescopic and forming a shock absorber. The two connecting rods also are coupled to a rocker (7) pivotally mounted on a central pivot (8), wherein the common pivot of the rocker beams is secured to a structure of an aircraft to which the undercarriage is fastened and is mounted in a fixed position on the structure. The central pivot of the rocker is movable between a first position (rocker beams in a landing position) and a second position in which a rocker has pulled on the connecting rods to cause the rocker beams to pivot towards a retracted position of the undercarriage.