An aspect of the invention provides a developing unit that includes: a developer; an image carrier on which an electrostatic latent image is formed; a first developer carrier configured to develop the electrostatic latent image formed on the image carrier by causing the developer to adhere to the electrostatic latent image; a first restriction member configured to be in press-contact with the first developer carrier; a second developer carrier configured to abut to the first developer carrier, and to form a developer layer on the second developer carrier; a second restriction member configured to abut to the second developer carrier; and a supplying member configured to supply the second developer carrier with the developer.