PURPOSE: To perform rolling high in quality and productivity from extra-thin material to thick material by providing a coupling means between an end part of the output shaft of a drive in a rolling mill and the end part of the drive side of a spindle coupling and changing spindle couplings according to the diameter of a working roll.

CONSTITUTION: In using working rolls 6A, 7A large in diameter, the output shafts 3A, 3B of the drive 3 are connected with the working rolls 6A, 7A through spindle couplings 2A, 2B large in diameter. Spindle couplings 2C, 2D small in diameter are held on an changing device. In using the working rolls 6B, 7B small in diameter, the output shafts 3A, 3B of the drive 3 are connected with the working rolls 6B, 7B through spindle couplings 2C, 2D small in diameter. The spindle couplings 2A, 2B large in diameter are held on the changing device.