Abstract: A screw connection device for connecting two pipes with flared ends, comprises a screw, a nut and a spacer. The nut has a front end aperture from which an accommodating space extends to a rear end aperture in a rear end wall. A surface of the nut in the accommodating space has a threaded section which extends toward the rear end wall which has a flange face in the accommodating space. In a pre-installed state, the spacer and a first pipe end with a first flare are accommodated in the nut, such that the spacer is held undetachable between the first flare and the internal thread. A second pipe end with a second flare can be held in the accommodating space by the screw, threaded into the nut such that the second flare is pressed against a sealing surface of the spacer and the spacer is pressed with a further sealing surface against the first flare.