The invention relates to a valve device that is used in oil and gas wells. The valve device has an external housing (1), where at least one inlet (4) in the housing (1) is connected to an outlet (5) through a longitudinal bore in the housing longitudinal direction. Between the valve device's inlet and outlet there is mounted a valve seat (2) in the bore, where a valve body (3) shuts off the connection between the inlet and outlet. The valve body's position is controlled by a support (20), connected with a pressure-sensitive bellows device (6) comprising an upper and a lower bellows element (7, 71). When the lower bellows element is compressed in the valve device's axial direction, the compression will cause the two bellows elements'impact elements to be moved relative each other in order to lift the valve body out of abutment with the valve seat.