The invention relates to a mechanical prosthetic heart valve (10) comprising: an annular support (12) having an internal peripheral wall (14) centered about a longitudinal axis (X) and delimiting an internal passage, and at least two mobile leaflets, preferably three mobile leaflets (40), arranged in such a way as to each be able to effect a rotational movement about an axis of rotation perpendicular to said longitudinal axis (X) so that the valve (10) can pass from a closed configuration to an open configuration and vice versa. Each leaflet (40) comprises a leading edge (42) designed to come against a portion of the internal peripheral wall (14) of the annular support (12) when the valve is in a closed configuration, an internal surface (46b) extending from the leading edge (42), and an external surface (46a) opposite the internal surface (46b) and extending from the leading edge (42). The annular support (12) comprises, on the internal peripheral wall (14), at least one lower bearing member (16a, 16b) per leaflet situated between two of said extensions (30) and designed to be in contact against the corresponding leaflet when the valve (10) is in the closed configuration, and two upper bearing members (20a, 20b). The two upper bearing members (20a, 20b) comprise each a distal end (21). Each distal end (21) is designed to come to bear against a bearing zone of the external surface (46a) of the leaflet (40). The center of the bearing zone is set back from the leading edge (42) of the leaflet (40) by a distance greater than a thickness of said leaflet at the center of said bearing zone.