A hydrodynamic type oil-impregnated sintered bearing includes a porous bearing body of sintered metal having a bearing surface opposed to a sliding surface of a rotating shaft, hydrodynamic pressure generating grooves slanting against an axial direction provided in the bearing surface, and lubricating oil or lubricating grease impregnated in pores inside the bearing body, wherein a rate of area of surface holes on the bearing surface is set within a range of 3%-15%, the surface holes being distributed substantially uniformly over the whole area of the bearing surface including areas of the hydronamic pressure generating grooves, wherein the lubricating oil or a base oil of the lubricating grease forms a lubricating film in a bearing clearance, and wherein the lubricating oil or a base oil of the lubricating grease is a lubricating oil selected from among mixtures of poly-α-olefin or hydrogenated compound thereof and a defined phosphoric ester.