The yield rate or the percentage of the weight of the ring-shaped member with respect to the weight of the raw material and the yield rate or the percentage of the ring-shaped member with respect to the blank are improved to achieve the cost reduction. A half-finished article 18 having large curved parts 3D obtained by widening the curved parts 3d so as to have a curvature radius larger than the initial curvature radius, and bulge-out parts 3E curved to a circular arc shape at a curvature radius larger than the curvature radius of the curved parts 3d at the linear parts 3b, 3c is molded, and thereafter, the half-finished article 18 is molded into an annular shape to obtain the ring-shaped member 1.

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