A developing device includes a first developing roller including a first transport member that transports magnetic developer by rotating while being close to a latent-image carrier rotating in one direction and a first magnet member, a second developing roller including a second transport member that transports the developer by rotating while being close to the latent-image carrier at a position on a downstream side of the first developing roller in the one direction, and a second magnet member, and a regulation member that regulates transport amounts of the developer distributed to the first and second developing rollers to required transport amounts, and opposes the developing rollers with predetermined distances therebetween. The first and second developing rollers are spaced from each other. The regulation member is movably supported in an area closer to the latent-image carrier than a closest position between the first and second developing rollers.