One preferred embodiment of the present invention provides a dynamic
pressure bearing formed of a porous material into a shape of a
cylindrical sleeve, for rotatably supporting a shaft inserted thereinto,
including a first groove portion being formed circumferentially in a part
of the inner circumferential surface of the dynamic pressure bearing; a
second groove portion being formed circumferentially in the inner
circumferential surface of the dynamic pressure bearing so as to have an
intervening portion of the inner circumferential surface of the dynamic
pressure bearing interposed between the first groove portion and the
second groove portion; and a connection groove formed in the intervening
portion so as to link the first groove portion and the second groove
portion, the connection groove having at a bottom surface thereof a
porous open ratio lower than a porous open ratio at any portion except
for the bottom surface in the intervening portion.