In an image forming apparatus, an exposure device performs exposure on a non-image area of image pattern, performs an exposure on the image area in an exposure amount lower than the non-image area or does not perform exposure, and an exposure amount control device controls, with respect to pixels having the same density data, an exposure amount given by an exposure device to be smaller in a first portion, which is a thin-line of a width that is equal to or less than a predetermined number of pixels or which is an isolated dot of widths that are equal to or less than the predetermined number of pixels in two directions substantially orthogonal to each other, than in a second portion which is a line of a width exceeding the predetermined number or a surface of widths that exceed the predetermined number in two directions substantially orthogonal to each other.