PURPOSE: To contrive labor saving by supporting an unused spindle with an idling shaft which is mounted to its bearing box when rolling with single-shaft driving in a two-shaft drive mill.

CONSTITUTION: When single-shaft drive rolling is performed for the purpose of 5 Hi rolling with smell diameter rolls or the like in a two-shaft drive mill (2 Hi, 4 Hi and 6 Hi, etc.), the unused spindle 9 is supported with the idling shaft which is mounted on the bearing box 5 corresponding to the shaft ends of nondriven intermediate roll shaft 2 or the same spindle 9. In this way, single- shaft drive rolling can be performed without demounting the unused spindle 9 and the time and cost for demounting and mounting can be drastically saved.