PURPOSE: To complete the connection to the roll shaft in one operation by sliding the intermediate stand on the common base, and to simultaneously execute the necessary position change according to the adjustment of the rolling reduction force of the roll stand.

CONSTITUTION: Couplings 21, 22 connected to the driving system by an expansion type universal joint are mounted on coupling holders 14, 15 mounted on the linear guide which is slidable in the vertical direction in a fine adjusting manner in the horizontal and vertical direction. The couplings 21, 22 are arranged opposite to the ends of roll shafts 31, 32 by lowering the elevated coupling holders 14, 15 and stopping them by the guides 14d, 15d for the automatic alignment while an intermediate stand 10 to hold the couplings is slid on the common base 1. This constitution completes the connection to the roll shaft in one operation while automatically adjusting the height without reading or adjustment of the coupling height, and the couplings are free in motion in the vertical direction to allow free adjustment of the rolling reduction force during the rolling operation.