A tapered roller bearing (10, 1010, 2010) comprising: an outer ring (11, 1011, 2011) including an outer-ring raceway surface (11A, 1011A, 2011A) around an inner circumferential surface; an inner ring (13, 1013, 2013) arranged on a radially inner side relative to the outer ring (11, 1011, 2011), the inner ring (13, 1013, 2013) including an inner-ring raceway surface (13A, 1013A, 2013A) around an outer circumferential surface and a larger flange surface (18, 1018, 2018) arranged on a larger diameter side relative to the inner-ring raceway surface (13A, 1013A, 2013A); and a plurality of tapered rollers (12, 1012, 2012) disposed between the outer-ring raceway surface (11A, 1011A, 2011A) and the inner-ring raceway surface (13A, 1013A, 2013A), the tapered roller including a rolling surface (12A, 1012A, 2012A) in contact with the outer-ring raceway surface (11A, 1011A, 2011A) and the inner-ring raceway surface (13A, 1013A, 2013A) and a larger end face (16, 1016, 2016) in contact with the larger flange surface (18, 1018, 2018), a value of R/R BASE being not smaller than 0.75 and not greater than 0.87, with R representing a reference radius of curvature of the larger end face (16, 1016, 2016) of the tapered roller and R BASE representing a distance from an apex of a cone angle of the tapered roller to the larger flange surface (18, 1018, 2018) of the inner ring (13, 1013, 2013), a nitrogen enriched layer (11B, 12B, 13B, 1011B, 1012B, 1013B, 2011B, 2012B, 2013B) being formed on at least one surface layer of the outer-ring raceway surface (11A, 1011A, 2011A) of the outer ring, the inner-ring raceway surface (13A, 1013A, 2013A) of the inner ring, or the rolling surface (12A, 1012A, 2012A) of the tapered rollers, characterized in that a distance from an outermost surface of the surface layer to a bottom of the nitrogen enriched layer (11B, 12B, 13B, 1011B, 1012B, 1013B, 2011B, 2012B, 2013B) being not shorter than 0.2 mm, the rolling surface (12A, 1012A, 2012A) of the tapered roller being provided with a crowning profile, and a sum of drops of the crowning profiles being expressed in a y-z coordinate system with a generatrix of the rolling surface (12A, 1012A, 2012A) of the tapered roller being defined as a y axis and a direction orthogonal to the generatrix being defined as a z axis, in an expression z y = A In 1 1 − 1 − exp − z m A y − a K 2 a + 1 2 where K 1, K 2, and z m represent design parameters, Q represents a load, L represents a length in a direction of the generatrix, of an effective contact portion of the rolling surface (12A, 1012A, 2012A) in the tapered roller, E' represents an equivalent elastic modulus, a represents a length from an origin on the generatrix of the rolling surface (12A, 1012A, 2012A) of the tapered roller to an end of the effective contact portion, and A is defined as A = 2K 1 Q/πLE'. an outer ring (11, 1011, 2011) including an outer-ring raceway surface (11A, 1011A, 2011A) around an inner circumferential surface; an inner ring (13, 1013, 2013) arranged on a radially inner side relative to the outer ring (11, 1011, 2011), the inner ring (13, 1013, 2013) including an inner-ring raceway surface (13A, 1013A, 2013A) around an outer circumferential surface and a larger flange surface (18, 1018, 2018) arranged on a larger diameter side relative to the inner-ring raceway surface (13A, 1013A, 2013A); and a plurality of tapered rollers (12, 1012, 2012) disposed between the outer-ring raceway surface (11A, 1011A, 2011A) and the inner-ring raceway surface (13A, 1013A, 2013A), the tapered roller including a rolling surface (12A, 1012A, 2012A) in contact with the outer-ring raceway surface (11A, 1011A, 2011A) and the inner-ring raceway surface (13A, 1013A, 2013A) and a larger end face (16, 1016, 2016) in contact with the larger flange surface (18, 1018, 2018), a value of R/R BASE being not smaller than 0.75 and not greater than 0.87, with R representing a reference radius of curvature of the larger end face (16, 1016, 2016) of the tapered roller and R BASE representing a distance from an apex of a cone angle of the tapered roller to the larger flange surface (18, 1018, 2018) of the inner ring (13, 1013, 2013), a nitrogen enriched layer (11B, 12B, 13B, 1011B, 1012B, 1013B, 2011B, 2012B, 2013B) being formed on at least one surface layer of the outer-ring raceway surface (11A, 1011A, 2011A) of the outer ring, the inner-ring raceway surface (13A, 1013A, 2013A) of the inner ring, or the rolling surface (12A, 1012A, 2012A) of the tapered rollers, characterized in that a distance from an outermost surface of the surface layer to a bottom of the nitrogen enriched layer (11B, 12B, 13B, 1011B, 1012B, 1013B, 2011B, 2012B, 2013B) being not shorter than 0.2 mm, the rolling surface (12A, 1012A, 2012A) of the tapered roller being provided with a crowning profile, and a sum of drops of the crowning profiles being expressed in a y-z coordinate system with a generatrix of the rolling surface (12A, 1012A, 2012A) of the tapered roller being defined as a y axis and a direction orthogonal to the generatrix being defined as a z axis, in an expression z y = A In 1 1 − 1 − exp − z m A y − a K 2 a + 1 2 where K 1, K 2, and z m represent design parameters, Q represents a load, L represents a length in a direction of the generatrix, of an effective contact portion of the rolling surface (12A, 1012A, 2012A) in the tapered roller, E' represents an equivalent elastic modulus, a represents a length from an origin on the generatrix of the rolling surface (12A, 1012A, 2012A) of the tapered roller to an end of the effective contact portion, and A is defined as A = 2K 1 Q/πLE'.