FLUID DYNAMIC PRESSURE BEARING DEVICE

PROBLEM TO BE SOLVED: To properly and quickly balance pumping force in thrust dynamic pressure bearing parts SBa, SBb with a simple constitution. SOLUTION: In this fluid dynamic pressure bearing device wherein a pair of thrust dynamic pressure bearing parts SBa, SBb communicate with each other to form a fluid circulating passage 23d for equalizing the pressure imbalance between both thrust dynamic pressure bearing parts SBa, SBb, the pressure imbalance of the lubricating fluid F can be equalized by moving the lubricating fluid F between the pair of thrust dynamic pressure bearing parts SBa, SBb through the fluid circulating passage 23d, even when the pressure imbalance of the lubricating fluid F caused by deformation of a thrust plate and the like, is generated in the thrust dynamic pressure bearing parts SBa, SBb, whereby the floatation amount in the thrust dynamic bearing parts SBa, SBb can be stabilized.