Abstract: The invention relates to a corona discharge device of the scorotron system which is used for electrophotographic copying machines. According to the device the invention, an impedance element 11 is connected between grid wires 6 and the ground, and generates a voltage depending upon a corona current which flows from a corona discharge wire 8 to the grid wires 6. Here, one end of the impedance element is connected to an electrically conductive shielding plate 3. The impedance element is formed in the discharger as a unitary structure, and only one connector is required for the corona discharge wire. Hence, the positioning operation is facilitated and poor electrical connection is avoided.