Abstract: The invention relates to a ball valve (3) with full opening between two tubes (1, 2) and the manufacturing method thereof. The ends (6, 7) of the tubes are sealed in the valve against the valve ball (5) opening and closing the valve and rotating about its axle (17), the diameters of the flow openings (9, 10) of the valve ball being substantially the same as the diameters of the flow cross sections of the tubes. Around the valve ball and the ends of the tubes there is a sleeve-like casing (8) secured by its ends (15) to the sides of the tubes (1, 2). According to the invention, a protrusion is formed in the ends of both tubes (1, 2), comprising an annular sealing (11), and the casing (8) is formed with a tapered reduction towards its ends so that the valve ball (5) and the ends of the tubes are located in the space (16) defined by the casing (8) of the valve.