The invention is a finishing treatment of lubricating oil after lubricating the hydro dynamic bearing device, specifically for wiping off the lubricating oil adhering to the outside of the housing and adjusting the oil-level height of the lubricating oil filled in the housing. The hydro dynamic bearing device comprising constructed of an axial member housed in a housing, a radial bearing part forsupporting the axial member in a non-contact manner in a radial direction by a hydro dynamic pressure action of the lubricating oil generated in a radial bearing clearance, and a sealing part arranged in an opening part of the housing. In a manufacturing process of the hydro dynamic bearing device and after a step of applying the lubricating oil to an unlubricated hydro dynamic bearing device, a gas is blown on the outer peripheral surface of the housing, while a suction device that generates a negative-pressure suction force is used to suck the lubricating oil from the sealing space of the sealing part or the vicinity thereof, which makes the treatment more proper and having a good efficiency.