In a dynamic pressure bearing apparatus having a fixed shaft, dynamic pressure generating grooves formed at least on one side of circularly facing surfaces of a rotor and of the fixed shaft which is rotatably meshed with the rotor, a radial bearing formed in an axial direction and a thrust bearing is formed by one end of the fixed shaft and axially facing surfaces of the rotor, the rotor is rotatably supported against the fixed shaft by air dynamic pressure which is generated in the radial bearing and the thrust bearing. The radial dynamic pressure bearing generating grooves are formed on the radial bearing in a dynamic pressure groove shape which pumps air pressure toward the thrust bearing side. An air guide hole is formed in the fixed shaft from the one end to another end of the fixed shaft. The dynamic pressure bearing apparatus comprises the thrust bearing, a pressure chamber, which stores air pumped from the radial bearing between the one end of the fixed shaft and the surface of the rotor facing the one end in the axial direction and a pressure adjuster constructed with small air passages from the pressure chamber and the air guide hole.