In a pressure valve inserted in a fuel supply conduit between a fuel injection pump and an injection vavle of the internal combustion chamber and comprising a valve member and a locking member cooperating with the valve member and opening in the direction of the fuel supply, and a back-pressure relief valve including a closing element which closes an axial bore of the locking member, a throttle orifice is provided in the connection between the axial bore of the locking member and an axial recess formed in the connection element connected to the fuel supply conduit leading to the internal combustion engine so that no after-injections occur, and a sufficiently great stable pressure is maintained in the fuel supply system.