A corona charger includes a case provided in the vicinity of a device to be charged. The case includes an opening facing the device, a discharge electrode, a first charging region, and a second charging region. The discharge electrode provided inside the case and supplied with a voltage so as to generate a corona discharge charges a surface of the device from the opening by supplying the corona discharge to the surface. The first charging region includes no grid electrode at a position upstream of the opening in a surface moving direction of the device. The second charging region includes a grid electrode to which a predetermined voltage is applied at a position downstream of the opening. The voltage applied to the discharge electrode is an alternating current (AC) voltage superimposed on a direct current (DC) voltage.