This invention is to provide a conductive grease which is less to decrease conductivity as a time passes. The conductive grease comprises abase oil, a thickener, a conductive solid powder, and at least one kind of a wear inhibitor, an extreme pressure agent and an oiliness agent, wherein an amount of the conductive solid powder added is 0.1 to 10 wt %, and an amount of the at least one kind of a wear inhibitor, an extreme pressure agent and an oiliness agent added is 0.1 to 10 wt %. Further, the conductive grease comprises the base oil and at least one of conductive additives, and the conductive additives are fibrous carbon, metallic particle, metallic compound particle and carbon nano-tube. The conductive grease to be packed into the rolling bearing comprises conductive fine particles such as carbon black and has an oil separation degree of 2% or lower. A ball bearing to be favorably used at high temperature comprises an inner race and an outer race, and a plurality of balls freely rotating between both races, and the conductive grease packed into a space defined between both races and holding the plural balls therein, and the conductive grease comprises the base oil, a thickener comprising fluorine compound or silicone compound and 0.2 to 10 wt % of the carbon black.