A developing device includes a developing roller and a conveyor roller. The developing roller includes a first magnet. The conveyor roller includes a second magnet. The first magnet includes a first magnetic pole and a second magnetic pole. The second magnet includes a third magnetic pole and a fourth magnetic pole. The first and fourth magnetic poles are magnetic poles having the same polarity. One of the second and third magnetic poles is a magnetic pole having the same polarity as the first magnetic pole. The other of the second and third magnetic poles is a magnetic pole having a polarity different from the first magnetic pole. The developer is transferred from the conveyor roller to the developing roller by the third and second magnetic poles. The developer is transferred from the developing roller to the conveyor roller by the first and fourth magnetic poles.