PROBLEM TO BE SOLVED: To provide a roller bearing for electric seat reclining that holds the number of rollers equivalent to that of a full-complement roller type, prevents the occurrence of a rattle feeling or the like when in operation, has excellent feeling characteristics, prevents a deterioration in responsiveness when started, achieves a long service lifetime, low torque, and low vibration, and also, prevents an increase in width dimension. SOLUTION: The roller bearing is used in an electric seat-reclining device and supports a backrest so as to allow the inclination angle of the backrest to be freely adjustable. The roller bearing has two inner and outer retainers 13, 23, and a plurality of rollers 2 held over pockets of the two retainers 13, 23. The inner retainer 13 is configured as follows. A column 5 between each pocket 4 holds the roller 2 between each roller 2 from the inner-diameter side. The outer diameter of the column 5 is smaller than a pitch circle diameter PCD of the roller arrangement. The outer retainer 23 is configured as follows. A column 5 between each pocket 4 holds the roller 2 between each roller 2 from the outer-diameter side. The inner diameter of the column 5 is larger than a pitch circle diameter PCD of the roller arrangement. COPYRIGHT: (C)2011,JPO&INPIT