A hydrodynamic bearing device capable of inhibiting leakage of a
working fluid to an outside of a bearing and preventing reduction in radial bearing rigidity, and capable of keeping a gap between a
thrust bearing and a radial bearing favorable and rotating stably. The hydrodynamic bearing device includes a shaft relatively rotatably inserted into a bearing hole of a sleeve, a radial
bearing surface having
dynamic pressure generating grooves formed on at least one of an outer
peripheral surface of the shaft and an inner
peripheral surface of the sleeve, and a gap filled with a
working fluid between the shaft and the sleeve. The shaft is made of high
manganese chrome steel or stainless steel, and the sleeve is entirely made of sintered
metal of
metal particles including at least 60% by weight of iron or
copper. Resin,
metal or water glass is impregnated in pores on a surface of the sintered metal and cured. Thereby, leakage of the
working fluid to the outside of the bearing from the sleeve can be inhibited, and reduction in the pressure inside the bearing can be prevented.