A tapered roller bearing, comprising: an inner ring having an inner raceway surface formed on an outer peripheral surface thereof; an outer ring having an outer raceway surface formed on an inner peripheral surface thereof; a plurality of tapered rollers arranged between the inner raceway surface of the inner ring and the outer raceway surface of the outer ring; and a retainer configured to retain the tapered rollers at a plurality of positions in a circumferential direction, wherein the retainer comprises: a small-diameter-side annular portion; a large-diameter-side annular portion; and a plurality of pillar portions connecting the small-diameter-side annular portion and the large-diameter-side annular portion to each other, wherein the tapered rollers are each received in a pocket which is defined by the small-diameter-side annular portion, the large-diameter-side annular portion, and adjacent two pillar portions of the retainer, wherein a plurality of projecting portions (45a, 45b), which are separated apart from both the small-diameter-side annular portion and the large-diameter-side annular portion in a roller axis direction and are configured to guide the tapered roller on distal end surfaces thereof, are formed on a side surface of each of the pillar portions of the retainer so as to be separated apart from each other in the roller axis direction, and wherein the projecting portions (45a, 45b) each have a force-fit margin, characterized in that a) a guide portion formed of a fracture surface is formed on a radially outer side of each of the distal end surfaces of the projecting portions (45a, 45b), and b) wherein a distance between the fracture surfaces of the projecting portions (45a, 45b) opposed to each other in the circumferential direction is larger on the radially outer side than on the radially inner side. an inner ring having an inner raceway surface formed on an outer peripheral surface thereof; an outer ring having an outer raceway surface formed on an inner peripheral surface thereof; a plurality of tapered rollers arranged between the inner raceway surface of the inner ring and the outer raceway surface of the outer ring; and a retainer configured to retain the tapered rollers at a plurality of positions in a circumferential direction, wherein the retainer comprises: a small-diameter-side annular portion; a large-diameter-side annular portion; and a plurality of pillar portions connecting the small-diameter-side annular portion and the large-diameter-side annular portion to each other, a small-diameter-side annular portion; a large-diameter-side annular portion; and a plurality of pillar portions connecting the small-diameter-side annular portion and the large-diameter-side annular portion to each other, wherein the tapered rollers are each received in a pocket which is defined by the small-diameter-side annular portion, the large-diameter-side annular portion, and adjacent two pillar portions of the retainer, wherein a plurality of projecting portions (45a, 45b), which are separated apart from both the small-diameter-side annular portion and the large-diameter-side annular portion in a roller axis direction and are configured to guide the tapered roller on distal end surfaces thereof, are formed on a side surface of each of the pillar portions of the retainer so as to be separated apart from each other in the roller axis direction, and wherein the projecting portions (45a, 45b) each have a force-fit margin, a) a guide portion formed of a fracture surface is formed on a radially outer side of each of the distal end surfaces of the projecting portions (45a, 45b), and b) wherein a distance between the fracture surfaces of the projecting portions (45a, 45b) opposed to each other in the circumferential direction is larger on the radially outer side than on the radially inner side.