Disclosed is an oil-impregnated sintered bearing in which local relative sliding between the oil-impregnated sintered bearing and the shaft is avoided, thereby mitigating stress concentration on the bearing surface of the oil-impregnated sintered bearing. An oil-impregnated sintered bearing 1 which has in its inner periphery a bearing surface 1a making relative sliding with the outer peripheral surface 22a of a shaft 22 and which has at both axial ends of the bearing surface 1a crowning portions 1c which are of a configuration satisfying the following conditions: 1.75.times.10.sup.-3.ltoreq..gamma./b1.ltoreq.5.2.times.10.sup.-2, and 1.75.times.10.sup.-3.ltoreq..gamma./b2.ltoreq.5.2.times.10.sup.-2, and 0.2.ltoreq.(b1+b2)/a.ltoreq.0.8, where .gamma. is the maximum radial drop amount of the crowning portions 1c, b1 is the axial length of the crowning portion 1c at one axial end; b2 is the axial length of the crowning portion 1c at the other axial end; and a is the total axial length of the oil-impregnated sintered bearing 1.