Disclosed is a method of manufacturing a charging roller useable in an electrophotographic image forming apparatus and a charging roller manufactured according to the method. The method includes introducing a conductive agent and a mixture of a rubber-based material and polyolefin-based resin into an extruder, extruding the conductive agent and the mixture to obtain an extrudate, crosslinking the extrudate by electron beam irradiation, and polishing the crosslinked extrudate. The method results in an environmentally friendly and simplified manufacturing processes, and/or in the reduction of the manufacturing costs.