Abstract: An image forming apparatus, having: an image carrier configured by a positively charged single-layer electrophotographic photosensitive body; a charging device which is based on a contact charging method for charging a circumferential surface of the image carrier while making contact with the circumferential surface of the image carrier; a developing roller which is disposed so as to oppose the image carrier and carry and convey toner on the circumferential surface; and a voltage application unit which applies a developing bias to the developing roller, wherein the frequency of an AC component of the developing bias applied by the voltage application unit is 2.6 to 4.2 kHz.