PURPOSE: To easily assemble and disassemble and to incorporate bearings of large capacities, by constituting of bearings at both the sides of operating and driving with the same bearings respectively, and bearing thrust load by the bearing either at the operating side or at the driving side.

CONSTITUTION: A roll is held between bearing boxes 11 and 11', into each of which a radial bearing 12 and a single row thrust bearing 13 are inserted from each shaft end in a state of being held by a bearing retainer 14 and a spring 15. The bearing boxes 11 and 11' are held by a projecting part (b) of a roll housing 5' at the driving side and a keeper plate 16 attached to a roll housing 5 at the operating side respectively. Mounting and dismounting at the time of roll replacing is performed only by operating the plate 16 attached to the housing 5 at the operating side without requiring any change of procedure as compared with that for a conventional construction.