PURPOSE: To enable reduced or expanded adaptation without exchanging shaping rolls having symmetrical caliber profiles by constituting the apparatus in such a manner that the central pivotal axes of the shaping rolls pass the range of the center of curvature in a circumferential segment of meshing parts or points apart a certain distance existing in the direction of the roll axes.

CONSTITUTION: The axes 15 of the shaping rolls exist at one common plane perpendicular to the tube axis and the shaping rolls are respectively pivotally and adjustably born around the pivotal axes 14 parallel to the tube axis. Each shaping roll is a type that the profile 11 of the shaping roll 3 delineating the contour of the meshing part has the radius of curvature larger than the radius of curvature of the peripheral surface segment to which the tube 9 traveling therein belongs. The pivotal axis 14 of the shaping roll 3 forming the profile symmetrical with respect to the central plane pass the range of the curvature center 12 in the contour segment of the meshing part to which the axis belongs or passes the point apart at the certain distance in the direction of the roll axis 15.