A medical connector (10, 112, 114, 116) of improved configuration. Annular grooves (54, 56) are formed in both inner and outer surfaces (50, 52) of an outer peripheral portion of an elastic valve element (38) to form an annular constricted section (58). An outer peripheral side from the constricted section (58) is made to serve as an annular fixation section (46). A valve receiving seat (68) is formed at an inner peripheral edge of an aperture portion (65) in a housing (12), and an annular ring (42) is fixed to the aperture portion (65) to sandwich and support the annular fixation section (46) between the valve receiving seat (68) and the annular ring (42). Engaging projections (70, 80) formed on mutually facing surfaces of the valve receiving seat (68) and the annular ring (42) are engaged with the annular grooves (54, 56), and either the engaging projection (70) and/or the engaging projection (80) is divided in a circumferential direction to have a plurality of projection-divisions (81).
