PURPOSE: To achieve the saving of energy and the reduction of equipment cost without degrading the bite characteristic of the material to be rolled by positively driving a pair of work rolls on the upstream side and positively driving only one of the other rolls.

CONSTITUTION: The upstream side rolling mill 1A are let to consist of a pair of positively driven work rolls 2, 3. With the downstream side rolling mills 1BW1F, the upper side work rolls 4 are let to be driven rolls and only the lower side work rolls are positively driven. The material 13 to be rolled is bitten between the work rolls 2, 3 of the upstream rolling mill 1A and with the pressing force being exerted thereto, it is bitten between the work rolls 4, 5 of the next rolling mill 1B. At this time, the biting is well accomplished by this pushing force and guiding of the rolls 2, 3. Next, in the rolling mill 1C as well, the biting is well accomplished by the pushing force and guidlng of the rolls 4, 5 of the rolling mill 1B. In this way, the good biting is accomplished subsequently down to the rolling mill 1F of the lowermost stream.