To provide a bearing device in which reliability for a long term is secured.

The protrusions 12Ab, 12Bb of inner rings 12A, 12B prohibit the relative rotation by the inner rings 12A, 12B, thereby controlling abrasion of end surfaces onto which the inner rings 12A, 12B are abutted and preventing reduction of the axial width of the inner rings 12A, 12B. By so doing, a proper clearance between conic rollers 14B, 14C is secured for the long term.