A tapered roller bearing comprising: an outer ring; an inner ring; a plurality of tapered rollers interposed between these rings (10, 20); and a retainer for retaining the tapered rollers, wherein the outer ring has a contact angle in a range of 25° to 30°, wherein a roller loading ratio represented by z·DW/(π·dm) is in a range of 0.7 to 0.92, and a ratio of roller length to roller diameter as represented by LWR/DW is in a range of 1.1 to 1.7, provided that z denotes a number of rollers, LWR denotes an effective length of the roller, DW denotes a mean diameter of the roller and dm denotes the Pitch Circle Diameter of the rollers, and wherein an outer-ring crowning parameter (= RCO/LRO) is in a range of 30 to 150, and an inner-ring crowning parameter (= RCI/LRI) is in a range of 50 to 260, provided that RCO denotes a radius of an outer-ring crowning, LRO denotes a raceway length of the outer ring, RCI denotes a radius of an inner-ring crowning, and LRI denotes a raceway length of the inner ring, wherein raceways (21, 11) of the outer ring and the inner ring and a rolling contact surface of the tapered roller are each provided with a crowning; a total crowning amount, which is the sum of an outer-ring crowning amount, an inner-ring crowning amount and twice a roller crowning amount, is 50 to 100 μm; an outer-ring crowning rate, which is the outer-ring crowning amount divided by the total crowning amount, is 40 to 85 %; a roller crowning rate, which is twice the roller crowning amount divided by the total crowning amount, is 20% or less, and an inner-ring crowning rate, which is the inner-ring crowning amount divided by the total crowning amount, is 10 to 55 %. an outer ring; an inner ring; a plurality of tapered rollers interposed between these rings (10, 20); and a retainer for retaining the tapered rollers, wherein the outer ring has a contact angle in a range of 25° to 30°, wherein a roller loading ratio represented by z·DW/(π·dm) is in a range of 0.7 to 0.92, and a ratio of roller length to roller diameter as represented by LWR/DW is in a range of 1.1 to 1.7, provided that z denotes a number of rollers, LWR denotes an effective length of the roller, DW denotes a mean diameter of the roller and dm denotes the Pitch Circle Diameter of the rollers, and wherein an outer-ring crowning parameter (= RCO/LRO) is in a range of 30 to 150, and an inner-ring crowning parameter (= RCI/LRI) is in a range of 50 to 260, provided that RCO denotes a radius of an outer-ring crowning, LRO denotes a raceway length of the outer ring, RCI denotes a radius of an inner-ring crowning, and LRI denotes a raceway length of the inner ring, wherein raceways (21, 11) of the outer ring and the inner ring and a rolling contact surface of the tapered roller are each provided with a crowning; a total crowning amount, which is the sum of an outer-ring crowning amount, an inner-ring crowning amount and twice a roller crowning amount, is 50 to 100 μm; an outer-ring crowning rate, which is the outer-ring crowning amount divided by the total crowning amount, is 40 to 85 %; a roller crowning rate, which is twice the roller crowning amount divided by the total crowning amount, is 20% or less, and an inner-ring crowning rate, which is the inner-ring crowning amount divided by the total crowning amount, is 10 to 55 %.