To perform improvement so that maintenance work or repair work of a bearing device can be started at any time in the monitoring method of the bearing device 1 provided with at least one bearing 2, 3, 4, 5 in the mounting member (housing) 6 of the roll journal bearing for back-up roll 8, intermediate roll 9 or work roll 10 in the rolling stand of a 2-high, 4-high, and 6-high single stand or a multi stand type rolling mill.

(a) The process amount W of the bearings 2, 3, 4, 5 or in the ranges adjacent to these bearings 2, 3, 4, 5 is measured. (b) The measured value of the process amount W is introduced to an evaluating device 13. (c) The measured value is compared with a stored set value Wmax/min. (d) The bearing device is monitored so that a signal is generated as soon as the measured value W exceeds or is less than the stored set value Wmax/min.