A roller inscribed circle R1 diameter of tapered rollers fitted in pockets of a bearing retainer is such that a circle R1 portion protruding radially outwardly of an inner race small flange radially outer surface when the rollers are at radially outermost positions in pockets with an outer race unmounted, and when the circle R1 is offset from a raceway circle center of an inner race raceway end at the flange so as to point contact the raceway circle. The circle R1 portion which does not radially outwardly protrude from the flange outer surface has a central angle >180° and ≦240°. Flange thickness is such that when the roller inscribed circle is offset from the raceway circle center to point contact the raceway circle, and swung about the contact point toward the flange, the flange does not interfere with the arcuate locus of the roller inscribed circle swing end.