Abstract: It is an object of the present invention to provide a method of manufacturing a cylindrical part with a thin-walled portion at a lower cost, and according to the manufacturing method of the present invention, a base metal formed with thin-walled portion adjacent to its closed end can be easily detached from working jigs. According to the method, a thin-walled portion is at first formed by the ironing process on a cylindrical wall adjacent to the closed end, so that an outer-side step portion is formed on an outer peripheral surface of the cylindrical wall. Then the closed end is punched out and the thin-walled portion is enlarged in a radial and outward direction to form an inner-side step portion on an inner peripheral surface of the cylindrical part.