To provide a roller bearing which can prevent retainer noise from being generated by stabilizing the lubricating state of a retainer guide surface, and prevent retainer deformation caused by a centrifugal force applied to the retainer, furthermore, smoothly rotate a ball held by the retainer by guiding it stably, additionally, reduce its manufacturing cost.

A retainer 5 is guided by the inner circumference surface 6 of an outer ring 3, and an annular grease sump recess 7 is formed at an end among guide surfaces of retainer outer diameters 5D guided by the inner circumference surface 6.