PURPOSE: To manufacture a roll product with high thickness accuracy by providing facility for roll eccentricity elimination control.

CONSTITUTION: Position detectors 7a, 7b are provided at the work sides of backup rolls 3, 4, and position detectors 7c, 7d at the diriving sides of them, and the change component of a backup roll gap is calculated by passing signals from them through computing elements 8, 9. A roll eccentricity detector 11 for a WS which outputs a roll gap correction signal to eliminate the change component and a roll eccentricity detector 12 for a DS are provided corresponding to the rotating position of a backup roll rotating position measuring instrument 10, and the roll gap signals of the roll eccentricity detectors 11, 12 passing through output adjusters 13, 14 are added on respective roll gap signal on the work side and the driving side. Moreover, an automatic plate thickness controller 15, support amplifiers 16, 27, and reduction cylinders 18, 19 are provided, which correct and control the roll gap on a WS side and a DS side independently.