A spindle motor, having a hydrodynamic pressure bearing, including: a stator including a core, on which at least one winding coil is wound, and a base provided with a central hole formed through the central area of the main body thereof so that the core is placed on the upper surface thereof; a rotor including a hub having a magnet formed on the outer circumference thereof to correspond to the winding coil leaving a designated interval with the winding coil, and a stop ring installed on the inner circumference of the hub; and a sleeve, for supporting the rotation of the rotor, including at least one dynamic pressure generating groove formed on the outer surface thereof correspondingly contacting the inner circumference of the hub and the stop ring, and a hub receiving hole formed through the central area of the main body thereof assembled with the central hole of the base.