A hydrodynamic bearing assembly includes a shaft; a sleeve having a shaft hole formed therein so that the shaft is rotatably inserted thereinto; and first and second dynamic pressure generation grooves provided in at least one of an outer surface of the shaft and an inner surface of the sleeve and having a herringbone pattern including V-shaped portions in which upper and lower wings are provided to generate dynamic pressure in lubricating fluid filling a bearing clearance between the shaft and the sleeve at the time of rotation of the shaft. The first dynamic pressure generation groove has a V-shaped portion of which an upper wing is longer than a lower wing, and the second dynamic pressure generation groove is disposed below the first dynamic pressure generation groove in an axial direction and has a V-shaped portion of which a lower wing is longer than an upper wing.