The invention relates to a device (1) for production of a tube (2) with a polygonal, preferably rectangular cross-section, comprising a tube welding unit (3), in which the tube (2) is formed from a sheet metal strip and welded at the resulting jointing position and a rolling unit (4), connected to the tube welding unit (3) in the transport direction (R) of the tube (2), which essentially rolls the tube (2) into the desired polygonal cross-sectional contour. According to the invention, right-angled tubes may be produced with the optimal geometry, whereby a camber rolling unit (5) is arranged in series with the rolling unit (4) in the transport direction (R) of the tube (2), by means of which at least two opposing tube sides (6, 7) may be rolled with a pair of crowned convex rollers (8, 9).