The inner ring and the outer ring and the ball bearing

A first fit portion (11) and a second fit portion (15) of an inner ring (1) according to the invention have a spring property. Therefore, the first and second fit portions (11, 15) may be flexed radially outward by elasticity thereof and then fitted to a shaft (20). Thus, the inner ring (1) is tightly fitted to the shaft (20) with a set interference with respect to the shaft (20). Accordingly, it is easy to fit/remove the inner ring (1) to/from the shaft (20). Therefore, an outer peripheral face of the shaft (20) is pushed radially inward by elasticity of the first and second fit portions (11, 15), that is, the inner ring (1) is tightly fitted to the shaft (20), without reducing the ease of fitting/removing the inner ring (1) to/from the shaft (20). As a result, it is possible to minimize generation of creep.