FLUID DYNAMIC PRESSURE BEARING DEVICE

PROBLEM TO BE SOLVED: To provide a fluid dynamic pressure bearing device capable of reducing a manufacturing cost while suppressing the increase of torque during the rotation of a shaft member.SOLUTION: The fluid dynamic pressure bearing device includes: an outer side member; a bearing member 8 which is arranged at the inner side of the outer side member and has radial dynamic pressure generating parts 8g1, 8g2 separated from each other on the inner circumferential surface in a shaft direction; and a shaft member 2 inserted to the bearing member 8. The sectioned part 82 of the radial dynamic pressure generating parts 8g1, 8g2 on the inner circumferential surface 8a of the bearing member 8 is protruded from areas P1 to P3. The outer circumferential surface of the shaft 2a of the shaft member 2 facing a portion between the radial dynamic pressure generating parts 8g1, 8g2 including the parts in the shaft direction on the inner circumferential surface 8a is made to be a single cylindrical surface.