A rolling bearing (1) having an inner ring (2); an outer ring (3); a plurality of rolling elements (4) interposed between the inner ring (2) and the outer ring (3); a retainer (5) retaining the rolling elements (4); and a seal (6) provided at an open portion, of the inner ring (2) and the outer ring (3), which is disposed at both axial ends thereof. The rolling bearing (1) is lubricated with a grease (8) enclosed in a space, inside the bearing, which is constructed of the inner ring (2), the outer ring (3), the retainer (5), and the seal (6).