Valve connector for infusion medical lines including an external tubular body (1) with an inlet end (4) and an outlet end (10), an internal hollow spike (2) and an intermediate sealing member (3) including an elastic head (35) with pre-slit (38) and an elastic hollow element (36) formed with sealing members (47, 48) in contact with the hollow spike (2) and with an elastic thrust means tending to maintain the elastic head (35) in a closure condition. An annular member (55) surrounds the elastic hollow element (36) and it axially slides into the tubular body (1) due to the movement of the elastic head (35) between the closure condition and the opening condition of the connector.