To provide a ring rolling mill which has a simplified equipment structure as a whole and makes it easy to recombine rolls, and attach and detach a ring.

In the equipment which consists of work rolls 5, 6 supported by the rolls at both sides, backup rolls 7, 8 and a tension unit to pull a ring material in the rolling direction, and has a three or four-tier rolling model comprising the work rolls and backup rolls, the rotating drive shafts are coupled with the work roll 5 and backup roll 8 supporting the work roll on which the ring material is put on, while avoiding the work roll 6 on which the ring material is put on, or coupled with both backup rolls 7, 8.