To provide an image forming apparatus capable of preventing charging failure of toner.

The image forming apparatus 100 includes: an image carrier disposed so as to be rotatable; a developer carrier having therein a magnet roller formed from a plurality of magnetic poles, and used for holding, on its peripheral face, developer composed of carrier and toner; a mixing-agitating section for supplying developer to the developer carrier; and a toner supply section for supplying toner to the developer in the mixing-agitating section. The toner supply section has: a charging section for precharging toner to be supplied; a supply roller 430 for holding toner charged by the charging section and for conveying toner to the mixing-agitating section; and an electrode 445 disposed opposite to the supply roller 430 without being in contact with it. At least part of a developer conveyance path for the mixing-agitating section in which developer is conveyed is disposed between the supply roller 430 and the electrode 445. A predetermined bias voltage is applied between the supply roller 430 and the electrode 445.