A medical connector having a substantially cylindrical shape, a first upper end for receiving a male luer, and a second lower end, and including: a disc shaped valve member arranged at the first upper end and having an uppermost surface and a lowermost surface, a slit formed at a center portion thereof, an upper groove formed in a circumferential edge portion of the uppermost surface, and a lower groove formed in a circumferential edge portion of the lowermost surface; a housing with a pedestal for supporting the disc shaped valve member; a protrusion projecting upwardly from the pedestal and being arranged in the lower groove; and an annular ring member disposed on the circumferential edge portion of the uppermost surface, and having a claw portion projecting downwardly and being arranged in the upper groove on the uppermost surface of the valve member.