A lubricating oil composition for fluid dynamic bearings which comprises 50 to 100% by mass of an ether compound comprising at least one ether bond and having 11 to 34 carbon atoms as the base oil and has a kinematic viscosity of at least 2.2 mm
2
/s at 100° C. is provided. The composition has excellent viscosity characteristics such as excellent fluidity at low temperatures and a small decrease in the viscosity in a high temperature range, exhibits lower evaporability, excellent energy saving property and excellent heat stability and is advantageously used for compact fluid dynamic bearings used under rotation at a high speed.