Abstract: A dynamic pressure gas bearing includes a stationary shaft defined by an upper portion, a diameter reduced middle portion having a circumferential grooves running therearound, and a lower portion. A plurality of slanted grooves are formed on the circumferential surface of the upper and lower portions so as to form a herringbone pattern. A rotating unit is mounded on the stationary shaft. When operation, the rotating unit is driven, the air in the gap between the stationary shaft and the rotating unit moves and collects at the circumferential groove. The collected air is guided through a tunnel extending from the side of the circumferential groove to the top end of the shaft 2. The pressurized air blows out toward the end surface of the rotating unit to perform a contactless rotation of the rotating unit.