ROLLING BEARING DEVICE

There is provided a rolling bearing apparatus which can more disperse stress which concentrates on a root portion of a flange portion formed on an outer circumferential surface of an outer ring as compared with a related art. In a rolling bearing apparatus 1, a surface which continues from a vehicle outer side end face 220 of an outer ring flange portion 22 to an outer circumferential surface 210 of an outer ring main body portion 21 is formed to have a smoothly continuing curved surface 200, and a protruding curved surface 203 which protrudes radially outwards is formed on a part of the curved surface 200.