PURPOSE: To improve a rolling quality of an annular product by making a shaft center line of a center roll cross a shaft center line of a main roll at a prescribed angle.

CONSTITUTION: A chock 5 is supported pivotally by a working table 7 on a vertical axis of the center of a center roll 2. A worm wheel 12 is provided on the end part on the chock 5, and also a worm 13 and its driving means 14 are fixed and placed on the working table 7. The worm 13 is rotated by the driving means 14, and the chock 5 is turned together with the worm wheel 12 to the minute extent through a center pin 8. By this mechanism a shaft center line of the center roll 2 is made to cross the center line of a shaft 3' of a main roll 3 at a prescribed angle. Accordingly, rolling between the center roll 2 and the main roll 3 is equalized in each part, and a rolling quality of an annular product whose inside periphery or outside periphery is tapered.