A rolling bearing for supporting a shaft on which a fan is provided, has an inner ring having an inner ring race on an outer surface thereof, an outer ring having an outer ring race on an inner surface thereof, balls provided between the inner ring race and the outer ring race and a retainer which keeps the balls apart each other in a circumferential direction, wherein an inner diameter of the bearing is set to be 3 mm or more and 17 mm or less, an outer diameter of the bearing is set to be 8 mm or more and 40 mm or less, when a thickness ti and a thickness te satisfies a relationship te.gtoreq.1.24 ti, and a residual austenite content in the inner ring is 7 wt % or less.