A fluid dynamic bearing device including: a bearing sleeve fixed to an inner periphery of a housing; a shaft member removably inserted along an inner periphery of the bearing sleeve; an annular member having an inner peripheral surface for defining a radial gap together with an outer peripheral surface of the shaft member; and radial bearing portions and a thrust bearing portion for supporting the shaft member. At least the radial bearing gap at each of the radial bearing portions, and a bottom gap having the thrust bearing portion received therein are filled with lubricating oil. A void section is formed in an interior space of the housing. Assuming that d1 represents a gap width of the radial bearing gap and d2 represents a gap width of the radial gap, a relationship of 30d1≦d2≦250d1 is satisfied.