To provide a roller bearing capable of preventing deformation of an inner ring caused by a state that interference between a shaft and the inner ring becomes tight in high-speed rotation, and also, capable of reducing torque without reducing rigidity and a rating load.

The roller bearing is provided with the inner ring 2 and an outer ring 4, which are arranged oppositely to each other so as to be relatively rotatable, a plurality of rolling bodies 6 arrayed between the inner/outer rings so as to be capable of freely rolling, and a seal plate 8 for preventing the leakage of a lubricant and the intrusion of foreign matters. The inner ring is fitted to the shaft with prescribed interference. The inner diameter of the inner ring is set almost to 6-18 mm. The roller bearing can rotate at a high speed of 80,000 rpm or more. When the pitch circle diameter of the rolling body is set as dm, the diameter of a virtual circle connecting the centers each other of the rolling bodies as PCD, the radius of the rolling body as r, the width of the roller bearing as W1, and a value obtained by subtracting the inner diameter of the inner ring from the outer diameter of the outer ring as W2, the relation of being 0.9dm<PCD<dm and 0.3>πr2/(W1×W2)>0.08 is satisfied.