A heel piece for an alpine ski attachment comprises a base element (1), fastenable to a ski (S), an upper element (2), coupled to the base element (1), and hooking means (3) borne by the upper element (2) for hooking to a shaped portion exhibited in a rear part of an alpine ski boot. The hooking means (3) comprise a pair of arms (31), constrained to the upper element (2) in such a way as to be rotatable with respect to the upper element (2), and a pair of pins (32) borne by the pair of arms (31) in such a way as to project from the upper element (2). The heel-piece further comprises elastic means (4) associated to the upper element (2) in such a way as to be in contact with the pins (32) and to maintain the pins (32) at a predetermined reciprocal distance. The elastic means (4) are stressable by a separation of the pair of pins (32), determined by a lowering of the rear part of the ski boot onto the ski and by insertion between the pins (32) of the shaped portion exhibited in said rear part. The pins (32) are destined, following complete insertion between the said pins (32) of the shaped portion, to be recalled by the elastic means (4) to near one another, in order to lock against an upper part of the shaped portion and thus to hook the ski boot.