A SrRuO.sub.3 conductive oxide sintered body characterized in that the relative density is 93% or more. By improving the additive amount and sintering conditions of Bi.sub.2O.sub.3, the present invention seeks to improve the relative density of a SrRuO.sub.3 conductive oxide sintered body, and to provide a conductive oxide sintered body capable of suppressing the generation of particles during sputtering upon forming a thin film and improving the quality and production yield; a sputtering target formed from such sintered body; and the manufacturing method thereof.