There is provided a hydrodynamic bearing assembly including: a sleeve against which a shaft is supported so that an upper end of the shaft, being compressed and inserted into a hub base of a rotor case, protrudes upwardly in an axial direction; a first thrust dynamic pressure generating part formed in at least one of a protrusion and the hub base corresponding to the protrusion, the protrusion being formed at an end of the sleeve along an inner diameter direction; and a second thrust dynamic pressure generating part formed around a protruding end portion of the sleeve, the protruding end portion facing an upper portion of a stopper part in the axial direction and the stopper part rotating together with the rotor case. Also, an oil sealing part has an oil interface between an outer circumferential surface of the sleeve along an outer diameter direction and an inner surface of the stopper part.