PURPOSE: To simplify a structure by arranging an intermediate pinion engaging with roll driving gears between the roll driving gears set to roll driving shafts of adjacent rolling stands and connecting an intermediate shaft providing this intermediate pinion with the above input shaft through a pair of bevel gears.

CONSTITUTION: When the input shaft 10 is rotated and driven by a driving device, the intermediate shaft 13 is rotated through a pair of bevel gears 11, 12 and a roll driving gear 15 at an adjacent rolling stand is rotated and driven by one intermediate shaft 13. The reduction ratio is determined by the number of teeth of the bevel gears 11, 12, the intermediate pinion 14 and the roll driving gear 15. Since the reduction ratio can be set to every adjacent rolling stand, the reduction ratio can be set easily. Further, since the roll driving gear 15 for the adjacent rolling stand is driven by one intermediate pinion, the structure can be simplified. Consequently, gears, bearings, etc., used normally can be used, a reduction gear excellent in maintainability can be obtained.