A bearing device includes a shaft having an axis, plural rolling bearings arranged at axially separated positions and rotatably supporting the shaft, a first cylindrical member for supporting the rolling bearings therein and having a first screw on a part of an outer surface thereof, a second cylindrical member having a second screw engaging with the first screw on an inner surface thereof and mounted to the outer surface of the first cylindrical member by engaging the first screw with the second screw, a restricting member provided on the outer surface of the second cylindrical member for preventing relative axial movement of the second cylindrical member with respect to the first cylindrical member when a portion of the second member contacts the restricting member.