Headrest of a motor vehicle seat, said headrest comprising: - a first structure for supporting a first support cushion, - a second structure for supporting a second support cushion, - a device for angular adjustment of said structures relative to each other about an axis of rotation, said headrest being characterised in that said angular adjustment device comprises a clamp deformable from a tightened latching configuration to a loose transition configuration, said clamp having the following characteristics: - it is made of a folded strip of spring metal, - it comprises two branches (7a, 7b) connected to one another by a central part, each of said branches comprising a sector (9a, 9b) of respective latching comprising a plurality of successive notches (10a, 10b) obtained by folding, each of said sectors registering generally in a respective circular arc, said circular arcs forming part of a circle of axis of revolution coincident with said axis of rotation, in such a way that a given notch of a sector corresponds to a notch diametrically opposite of the other sector, two opposite notches (10a, 10b) defining a latched position of angular adjustment, - it is fixedly mounted on said first structure, said angular adjustment device further comprising two latching protrusions (11a, 11b) stemming from said second structure, said projections being disposed on either side of a diameter of said circle so as to be able to engage in two notches (10a, 10b) diametrically opposed to said clamp in tightened configuration, the transition from one angular position to the other making a deformation of said clamp toward its loose configuration against an elastic return force returning it towards its tightened configuration. - a first structure for supporting a first support cushion, - a second structure for supporting a second support cushion, - a device for angular adjustment of said structures relative to each other about an axis of rotation, said headrest being characterised in that said angular adjustment device comprises a clamp deformable from a tightened latching configuration to a loose transition configuration, said clamp having the following - it is made of a folded strip of spring metal, - it comprises two branches (7a, 7b) connected to one another by a central part, each of said branches comprising a sector (9a, 9b) of respective latching comprising a plurality of successive notches (10a, 10b) obtained by folding, each of said sectors registering generally in a respective circular arc, said circular arcs forming part of a circle of axis of revolution coincident with said axis of rotation, in such a way that a given notch of a sector corresponds to a notch diametrically opposite of the other sector, two opposite notches (10a, 10b) defining a latched position of angular adjustment, - it is fixedly mounted on said first structure, said angular adjustment device further comprising two latching protrusions (11a, 11b) stemming from said second structure, said projections being disposed on either side of a diameter of said circle so as to be able to engage in two notches (10a, 10b) diametrically opposed to said clamp in tightened configuration, the transition from one angular position to the other making a deformation of said clamp toward its loose configuration against an elastic return force returning it towards its tightened configuration.