A developing agent carrying member including magnets is disposed facing an
image carrying member, a two-component developing agent containing toner
and magnetic carrier is carried in a form of a layer on a surface of the
developing agent carrying member, speed difference is generated between
the developing agent carrying member and the magnets so as to cause a
magnetic brush to flow while forming the magnetic brush on a developing
agent layer at least in a facing region where the developing agent
carrying member and the image carrying member face one another, and free
toner separated from magnetic carrier in a flow of the magnetic brush
adheres onto a latent image formed on the image carrying member, whereby
developing is performed. A line-shaped latent image is developed with the
toner starting from a middle portion thereof in a width direction of the
line-shaped latent image.