To provide a bearing device for a wheel which improves durability by securing an appropriate preload during straight running and appropriate bearing rigidity during turning and which achieves cost reduction by flexibly responding to each bearing specification.

A diameter of pitch circle of double row ball groups is set larger at the outer side than the inner side. An inner rolling face 6a of an inner ring 6 is structured with a radius r of curvature, which is formed over a range from the vicinity of a contact point P contacting the balls 4 at an initial contact angle α to a groove bottom and a radius r1 of curvature, which is smaller than the radius r of curvature and formed over a range from an inflection point P1 contacting the balls 4 at the contact angle α1 to a large outer diameter 6b of the inner ring 6. The radii r, r1 of curvature are set to the ranges of 1.05d<2r≤1.10d and 1.01d≤2r1≤1.05d with respect to the diameter d of the balls. When the inflection point P1 of the two radii r, r1 of curvature is determined as α1=α+Δα under α=30 to 45°, Δα is set to the range of 2 to 8°.

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