To provide a backup roll bearing device for reducing the number of part items, easy in assembling, having the long bearing service life, and usable over a long period.

A radial load loading radial bearing 14 and a thrust load loading ball bearing 15 arranged outside in the axial direction of this radial bering 14, are interposed between a roll 13 and a shaft 12. A seal member 26 for sealing an annular space formed between its inner-outer races 15a and 15b, is arranged only in a position on the opposite side of the adjacent side to the radial bearing 14 in the ball bearing 15.