A fluid dynamic bearing includes a bearing member (30) axially defining an inner bearing hole therein, and a spindle shaft (20) rotatably received in the bearing hole with a bearing clearance formed between an inner periphery of the bearing member and an outer periphery of the spindle shaft. Lubricant is filled in the bearing clearance. One of the inner periphery and the outer periphery comprises a bearing surface (10) with channels formed therein. The channels form a plurality of outer communication ends (1316b) at opposite sides of the bearing surface in the axial direction of the bearing member.