The invention has plural plate-like members, each molded by a metal die using a synthetic resin material in a shape having pockets for retaining rolling elements. A shape obtained by mutually connecting each of the plural plate-like members with connecting portions at both ends is a substantially cylinder shape. A shape of a section between both end portions of each plate-like member has a convex warped shape constituting a part of the cylinder by being subjected to a distortion action owing to heat contraction after being molded by the metal die.