A fluid dynamic bearing mechanism includes a stationary shaft, a sleeve portion arranged to rotate with respect to the shaft, and a thrust portion including an upper end surface arranged oppose to a lower end surface of the sleeve portion. An inside surface of the thrust portion includes an inside surface contact portion arranged in contact with an outside surface of the shaft, and an inside surface lower non-contact portion spaced away from the outside surface of the shaft, and arranged to extend downward from a lower end of the inside surface contact portion. An outside surface of the thrust portion includes an outside surface inclined portion arranged in contact with an interface of a lubricating oil. The lower end of the inside surface contact portion is arranged at a level axially higher than that of a lower end of the outside surface inclined portion.