A spindle motor having a hydrodynamic pressure bearing includes a stator,
a rotor, and a dynamic pressure generating unit including a sleeve having
an upper plate disposed opposite to the rotor and at least one thrust
dynamic pressure groove formed either at the upper plate of the sleeve or
at the rotor. Inside width from a neutral radius to an innermost radius
of the thrust dynamic pressure groove is larger than outside width from
the neutral radius to an outermost radius of the thrust dynamic pressure
groove such that the neutral radius is biased to the outside of the
thrust dynamic pressure groove. Dynamic pressure at the inside width of
the thrust dynamic pressure groove is higher than dynamic pressure at the
outside width of the thrust dynamic pressure groove such that fluid
supplied into the thrust dynamic pressure groove is guided to the outer
diameter side.