| 摘要 |
A ball body is formed with a mold having upper and lower mold half. Dimples 16 having a shape inverted from the shape of the pimples of the mold are formed on the ball body. The dimples 16 in the vicinity of the equatorial line have a size in the meridional direction D1 being greater than a size in the latitudinal direction D2. The difference between the size in the meridional direction D1 and the size in the latitudinal direction D2 is 0.01 mm or greater and 0.50 mm or less. By grinding the ball body in the vicinity of the equatorial line, a flash generated on the seam resulting form the mold is removed. According to the grinding, the size in the meridional direction of the dimple 16 is reduced, and thus, plane shape of the dimple becomes closer to a perfect circle.
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