A developing device includes: a housing, a refill developer storage part, a developing roller, a developer conveyance path, a developer receiving port, a conveyance member, and a magnetic member. The developing roller is driven into rotation in the developing housing and carries a toner on a circumferential surface thereof. The toner is conveyed inside the first conveyance path and the second conveyance path of the developing housing in a circulating manner. A first stirring screw is disposed on the first conveyance path and conveys the toner in a first direction. Downstream of the toner refill port, a magnet is arranged. The magnetic member forms a magnetic brush from a top panel of the developing housing towards the first stirring screw. A refill toner flowed-in through the toner refill port is so conveyed as to fall below the magnetic brush whereby the refill toner is favorably stirred with a surrounding toner.