To provide a gas dynamic pressure bearing device and a motor equipped with it capable of widening the selectability of the material of the stationary side and the rotary side and reducing the change in the size of the gap generated by a temperature change.

The gas dynamic pressure bearing device is equipped with shafts 22 and 23, a sleeve 32 whose inside surface confronts the outside surface of the shaft 23 through a micro-gap 32b to work as a gas dynamic pressure bearing, and a hub 31 approximately in a cylindrical shape fitted on the sleeve 32 while a surface pressure is applied and is structured so that dynamic pressure generating grooves 23a and 23b are formed at least at either of the outside surface of the shaft 23 and the inside surface of the sleeve 32, wherein the condition α1<α0<α2 should be met, where α0, α1, and α2 are the coefficients of linear expansion of the shaft 23, the sleeve 32, and the hub 31.