A corona discharging device of the type using a wire and for use with an electrophotographic copier or similar apparatus which effects an electrostatic process. Any of end blocks which are located at opposite ends of a shield case and made of an insulating material accommodates therein a conductive member in the form of a spring which is connected to a corona wire. A generally hollow cylindrical end block cover is made of an insulating material and configured to surround at least that part of the end block in which the spring is disposed. The end block cover is slid on and along the outer periphery of the end block along the axis of the cover into and out of engagement with the end block. The device may serve as a charger for charging a photoconductive element, a discharger for discharging it, or a precleaning discharger of a cleaning unit.