There is provided a fluid dynamic bearing assembly including: a sleeve having a shaft insertedly mounted therein; and upper and lower radial bearing parts formed on at least one of an outer circumferential surface of the shaft and an inner circumferential surface of the sleeve, wherein a clearance between the lower radial bearing part and a surface disposed to face the lower radial bearing part is wider than a clearance between the upper radial bearing part and a surface disposed to face the upper radial bearing part.