A scorotron charging device applicable to electrophotographic image forming equipment and having a main charger with discharge wires and a grid and applying voltages to the wires and the grid by respective power sources. The two power sources are controlled by the same control signal. In response to the control signal, a voltage starts being applied to the grid before a voltage is applied to said wires and ends being applied to the grid after the voltage application to the wires has ended. This allows the charge potential of a photoconductive element to rise and fall rapidly.