A rolling bearing, comprising: an inner race and an outer race rotatable relative to each other; a plurality of rolling elements interposed between the inner race and the outer race; a retainer arranged between the inner race and the outer race, for retaining the plurality of rolling elements equiangularly; a flange portion (20, 21, 22, 23) formed on at least one of a radially inner side and a radially outer side of an axial end portion of the retainer so as to extend radially; and a recessed groove (32, 33) formed in a region of the inner race corresponding to the flange portion (20, 23) or a region of the outer race corresponding to the flange portion (21, 22) so as to form a labyrinth together with the flange portion, wherein at least one of an inner side surface (34, 35, 36, 37) of the flange portion (20, 21) and an axial end surface of the recessed groove (32, 33), which is opposed to the inner side surface (34, 35, 36, 37) of the flange portion, is inclined radially so as to generate a flow of lubricant, wherein through the labyrinth formed by the flange portion (20, 21, 22, 23) and the recessed groove (32, 33), the lubricant flowing from an outside of the bearing into an inside of the bearing and flowing out of the inside of the bearing to the outside of the bearing flows in such a direction that the lubricant flows into the bearing from one axial end side of the retainer and flows out of the bearing to another axial end side of the retainer, and wherein the inner side surface of the flange portion positioned on the radially inner side of one axial end portion of the retainer is inclined so as to expand the labyrinth radially inward, wherein the inner side surface of the flange portion positioned on the radially outer side of the one axial end portion of the retainer is inclined so as to expand the labyrinth radially inward, wherein the inner side surface of the flange portion positioned on the radially outer side of another axial end portion of the retainer is inclined so as to expand the labyrinth radially outward, and wherein the axial end surface of the recessed groove positioned at an axial end portion of the outer race is formed in a direction orthogonal to an axial direction of the rolling bearing. an inner race and an outer race rotatable relative to each other; a plurality of rolling elements interposed between the inner race and the outer race; a retainer arranged between the inner race and the outer race, for retaining the plurality of rolling elements equiangularly; a flange portion (20, 21, 22, 23) formed on at least one of a radially inner side and a radially outer side of an axial end portion of the retainer so as to extend radially; and a recessed groove (32, 33) formed in a region of the inner race corresponding to the flange portion (20, 23) or a region of the outer race corresponding to the flange portion (21, 22) so as to form a labyrinth together with the flange portion, wherein at least one of an inner side surface (34, 35, 36, 37) of the flange portion (20, 21) and an axial end surface of the recessed groove (32, 33), which is opposed to the inner side surface (34, 35, 36, 37) of the flange portion, is inclined radially so as to generate a flow of lubricant, wherein the inner side surface of the flange portion positioned on the radially outer side of the one axial end portion of the retainer is inclined so as to expand the labyrinth radially inward, wherein the inner side surface of the flange portion positioned on the radially outer side of another axial end portion of the retainer is inclined so as to expand the labyrinth radially outward, and wherein the axial end surface of the recessed groove positioned at an axial end portion of the outer race is formed in a direction orthogonal to an axial direction of the rolling bearing.