Needle roller bearings have a cylindrical needle-type roller with a comparatively small diameter, where the length is greater than the diameter. Needle roller bearings have small cross-sectional height, and compared with other types of bearings, feature high load capacity and rigidity compared to the space taken by the bearing. Another feature is the low inertial force, which is appropriate for oscillating motion. Using these bearings, it is possible to make mechanical equipment smaller and lighter in weight. Also, it is easy to replace a sliding bearing with a Needle roller bearing.