In a development device which develops an electrostatic image formed on a rotating photosensitive drum by applying a development bias to a development sleeve bearing a two-component developer, the development device includes a specific pattern determination portion which determines whether or not the electrostatic image includes a specific pattern. When the development device develops the specific pattern electrostatic image determined by the specific pattern determination portion, a potential difference between a development sleeve and a first non-image part of a predetermined range which is adjacent to the specific pattern electrostatic image and located on an upstream side in a photosensitive drum rotating direction is set smaller than a potential difference between the development sleeve and a second non-image part which is different from the first non-image part.