A pivot assembly bearing capable to decrease the pressing force when it is pressed into a mounting hole of a swing arm and to prevent the formation of particles on the outer circumferential surface of a sleeve of pivot assembly bearing is provided. The pivot assembly bearing comprises a shaft, and a sleeve 13 rotatably supported around the shaft, a plurality of grooves extending along a circumferential direction are successively formed in an axial direction on an outer circumferential surface of the sleeve 13, and the surface roughness of the outer circumferential surface of the sleeve 13 is 0.5 to 8 μm in terms of center line average roughness (Ra) and 5 to 30 μm in terms of maximum height (Rmax).