To provide a bearing unit wherein optimization of rigidity and reduction of torque are simultaneously satisfied, while increasing speed and improving precision of control of an object to be borne.

The bearing unit 1 is furnished with a sleeve 8 capable of assembling a shaft 2 and a plurality of bearings 4, 6 and integrally molding a steppe part 8a to hold the bearings with a specified interval, and each of the bearings is provided with an inner ring 10 on which an inner ring inside diameter surface S1 and an inner ring raceway surface R1 forms a round shape and an outer ring raceway surface R2 forms an oval shape. A radial clearance in the major axial direction X is set larger than a radial clearance in the minor axial direction Y on the outer ring raceway surface R2. Radial rigidity in the minor axial direction of the outer ring raceway surface is set larger than radial rigidity in the major axial direction in a state of giving a specified pre-load by assembling the bearings on the sleeve. A mark M free to visually confirm the major axial direction and the minor axial direction of the oval outer ring raceway surface is attached on each of the bearings.