PURPOSE: To perform bending work smoothly by installing a holding device, for passing and holding a stock, and a bending roll device for bending its axial line, as well as sliding the holding device in accordance with the radius of bending curvature.

CONSTITUTION: A stock of strip M1 is formed into a continuous molding stock M2 by a roll forming machine 10 and is introduced to a holding device 30. The device 30 is formed by arranging plural pairs of right and left loosely fitted rolls to support the stock M2 slidably in a straight line as well as to slide in a whole body through the intermeshing of rack and pinion. A bending roll device 40 rocks laterally a base plate 41 with respect to the advancing direction of stock M2 through a cam plate 45 with a supporting axis 44 as the center. By this mechanism, the bending is performed by sliding the device 30 reversely to the bending direction in accordance with the radius of bending curvature when the bending radius is small. Accordingly, the bending of a small radius of bending curvature is smoothly performed.