Abstract: A device for mounting a mobile part of an automobile vehicle headlight on a relatively fixed part comprises a generally spherical head joined to a first part by means of a rod. A substantially complementary cavity is fastened to the second part. The head is forced fitted into the cavity through an opening into the latter. At least one flexible tongue is provided in the vicinity of the cavity and is adapted to deform elastically to enable insertion of the head therein and, after such insertion, to impede extraction of the head from the cavity. The cavity defines a stable position for the head in which the flexible tongue(s) are not in contact with the head. The device is used to adjust the reflectors relative to the headlight units.