Ball bearing

A ball bearing comprising:

• an inner ring being deformable;
• an outer ring being deformable and installed outside the inner ring;
• a plurality of rolling elements having a spherical shape and provided between the inner ring and the outer ring;
• and
• a cage provided with a plurality of pockets respectively accommodating the plurality of rolling elements, wherein the rolling elements and the pockets separated by gaps in a circumferential direction, wherein
• each of the plurality of pockets includes
• a pocket surface being a surface spread about an axial line extending in a radial direction, and
• a flange part being a portion protruding from the pocket surface toward the axial line side,
• the pocket surface is configured to accommodate a rolling element with a gap interposed between the pocket surface and the rolling element,
• the flange part is configured to come into contact with the rolling element positioned at at least a position of a minor radius of the inner ring from an inner side in the radial direction, or come into contact with the rolling element positioned at at least a position of a major radius of the inner ring from an outer side in the radial direction and
• the flange part includes a relief part on an opposite side of the pocket surface in a direction of the axial line from the portion contacting with the rolling element.