A double row tapered roller bearing comprising: an outer ring serving as a bearing ring having an annular shape; an inner ring disposed on an inner circumferential side of the outer ring and serving as a bearing ring having an annular shape, the inner ring having an outer circumferential surface facing the outer ring and having two rows of grooves having a bottom surface serving as a raceway surface; and tapered rollers disposed in the grooves in contact with the raceway surface of the inner ring and being also in contact with the outer ring, at the outer circumferential surface of the inner ring, a region adjacent to the groove including a hardened region extending from an inner peripheral surface of the groove to the region adjacent to the groove, and an unhardened region located at a position farther from the groove than the hardened region and being smaller in hardness than the hardened region, the inner ring being constituted of steel containing at least 0.43 mass % and not more than 0.65 mass % of carbon, at least 0.15 mass % and not more than 0.35 mass % of silicon, at least 0.60 mass % and not more than 1.10 mass % of manganese, at least 0.30 mass % and not more than 1.20 mass % of chromium, and at least 0.15 mass % and not more than 0.75 mass % of molybdenum with the rest consisting of iron and an impurity, wherein an angle that the raceway surface forms with a central axis of the inner ring is 40° or more and 50° or less; characterized in that in outer circumferential surface, a distance from an end of the opening of groove to an end of hardened region is set to 2 mm or more and 10 mm or less. an outer ring serving as a bearing ring having an annular shape; an inner ring disposed on an inner circumferential side of the outer ring and serving as a bearing ring having an annular shape, the inner ring having an outer circumferential surface facing the outer ring and having two rows of grooves having a bottom surface serving as a raceway surface; and tapered rollers disposed in the grooves in contact with the raceway surface of the inner ring and being also in contact with the outer ring, at the outer circumferential surface of the inner ring, a region adjacent to the groove including a hardened region extending from an inner peripheral surface of the groove to the region adjacent to the groove, and an unhardened region located at a position farther from the groove than the hardened region and being smaller in hardness than the hardened region, the inner ring being constituted of steel containing at least 0.43 mass % and not more than 0.65 mass % of carbon, at least 0.15 mass % and not more than 0.35 mass % of silicon, at least 0.60 mass % and not more than 1.10 mass % of manganese, at least 0.30 mass % and not more than 1.20 mass % of chromium, and at least 0.15 mass % and not more than 0.75 mass % of molybdenum with the rest consisting of iron and an impurity, wherein an angle that the raceway surface forms with a central axis of the inner ring is 40° or more and 50° or less; characterized in that in outer circumferential surface, a distance from an end of the opening of groove to an end of hardened region is set to 2 mm or more and 10 mm or less.