To provide a roller bearing capable of securing the integration of cage segments, rollers and an inner ring to allow easy assembly.

A first rim part 21 of one of adjacent cage segments has a first extension portion 21a extending toward the side of the other cage segment. A second rim part 22 of the other cage segment has a second extension portion 22a extending toward the side of one cage segment and opposed to the first extension portion 21a in the axial direction. First and second protruded portions 7, 8 provided on the first and second extension portions 21a, 22a and first and second recessed portions 11, 12 provided in end faces 4a, 4b on both axial sides of tapered rollers 4 stored in pockets 24 between the first and second extension portions 21a, 22a are fitted to each other to rotatably connect the tapered rollers 4 to the first and second extension portions 21a, 22a.