The invention delivers a charging roller which is capable of preventing current leakage to a photoreceptor throughout life-time and which has a stable resistance value throughout life-time. The charging roller contains a metal core and a rubber layer formed on the core. The rubber layer is an epichlorohydrin-based rubber base material to which an electronic conductive agent and an ionic conductive agent are added. The rubber layer is subjected to surface processing by spraying the surface with a solution containing an isocyanate compound and heating. The amount of the electronic conductive agent added to the rubber base material is limited so that a volume resistivity when only the electronic conductive agent is added to the rubber base material is 1.46.times.10.sup.6 .OMEGA.cm or greater. In addition, the amount of the added ionic conductive agent is increased so that a volume resistivity when the electronic conductive agent and the ionic conductive agent are added to the rubber base material is 1.93.times.10.sup.6 .OMEGA.cm or less.