To provide a bearing device having superior rotational smoothness and durability that suppresses the occurrence of deterioration of pressurization in a bearing means caused by thermal expansion and the occurrence of a gap between an outer peripheral part of the bearing means and an inner periphery of a supporting means.

As this bearing device includes suppressing rings 26a, 26b press-fitted to an outer periphery of supporting parts 18a, 18b of a housing 18 and having a rate of thermal expansion smaller than that of the supporting parts 18a, 18b, thermal expansion occurring during high temperatures in the radial direction of the supporting parts 18a, 18b is suppressed by the suppressing rings 26a, 26b. As a result, lowering of pressurization in the radial direction applied to tapered roller bearings 24a, 24b is suppressed, and occurrence of a gap is suppressed between the supporting parts 18a, 18b and outer rings 24e, 24f of the tapered roller bearings 24a, 24b, to enhance rotational smoothness and durability.