PURPOSE: To facilitate the additional reduction of the diameter of a shaft by setting the axial center of a bearing part in near the position where the center overlaps axially on a base part or the axial direction of a base part.

CONSTITUTION: The center (c) of the bearing surface α of the bearing part 10a' is set in the position where the center overlaps axially on the mounting base 10b'. Then, this bearing 10' has the high strength to bending in a bent part A between the bearing part 10a' and the mounting base part 10b'. The center (c) of the bearing surface α may not always be in the axially overlapping position and may be in the position where the center (c) of the bearing surface αis extremely nearer the mounting base part 10b' than heretofore in the relation with a sheet thickness.