Abstract: The needle roller bearing B in this embodiment comprises a cage 1 having a plurality of elongated window-shaped pockets 1a formed therein at predetermined circumferential intervals, and a plurality of needle rollers 2 rollably received and held in the pockets 1a. The four corners A of each pocket 1a of the cage 1 are provided with relief portions 1an4 each having a circumferentially recessed arcuate peripheral wall surface. The circumferential dimension between the circumferential top 1a41 of the relief potion 1a4 and the pocket wall surface 1a1 is set with respect to the diameter Dw of the needle rollers 2 such that 0.01.ltoreq.h/Dw.ltoreq.0.2. The provision of the relief portions 1a4 at the corners A of each pocket 1a of the cage 1 permits the relief portions 1a4 to serve as passageways for the lubricating oil.

Abstract: The needle roller bearing A comprises a cage 3 having a plurality of long window-shaped pockets 3a formed at an appointed interval on its circumference, and a plurality of needle rollers 4 rollably accommodated and retained in the pockets 3a of the cage 3. The connection radius R (radius of curvature) between the inner diameter side portion of the pocket wall surface 3a1 and the inside surface 3b1 of the annular portion 3b, and the connection radius R (radius of curvature) between the inner diameter side portion of the pocket wall surface 3a2 and the inside surface 3b1 of the annular portion 3b of the cage 3 are set to a value having a relationship of 0.2<R/Dr.ltoreq.0.5, preferably 0.3.ltoreq.R/Dr.ltoreq.0.5 with respect to the diameter Dr of the needle roller 4.