A developing device includes a developer carrier that has a cylindrical shape and that rotates while holding developer to supply the developer to an image carrier on which an electrostatic latent image is formed; a container that contains the developer carrier; a discharge-path forming member that forms a discharge path along which air is discharged out of the container from inside the container; and a magnetic member that generates a magnetic field that acts on the developer in the discharge path and causes the developer to stay in the discharge path.