A method of manufacturing a charge roller utilizes a foam rubber substance where epichlorohydrin oxide rubber and an acrylonitrile butadiene rubber are mixed at a ratio of 5:95, or utilizing a crosslinking rubber substance consisting of epichlorohydrin oxide rubber and acrylonitrile butadiene rubber having a polar low molecular polymeric characteristic, thus allowing the charge roller to maintain a low volume resistivity of 107 nullcm to 108 nullcm. As a result, the surface of a photosensitive drum can be charged by a minimum charging voltage, to thereby significantly reduce an amount of ozone. A method of manufacturing a charge roller employs peroxide as a cross linking agent for rapidly cross-linking molecular chains between an epichlorohydrin oxide rubber and acrylonitrile butadiene rubber forming a main composition of a foam rubber substance. Since a non-crosslinked low molecular polymeric substance existing at a resilient rubber is significantly reduced, the low molecular polymeric substance of the charge roller may not be migrated onto a surface of the photosensitive drum even if the charge roller is in contact with a photosensitive drum for a long time period during a stoppage of operation of an image forming apparatus, As a result, the charge roller may not cause an abnormal phenomenon on the surface of the photosensitive drum.