To provide an image forming apparatus which can image by correcting an image formation signal by a space digital filter with effects of a development condition or an environmental condition taken into account, thereby easing an edge highlighting effect.

There are set the space digital filter equipped with a plurality of filter conditions for easing the edge highlighting effect, a table which relates the filter conditions corresponding to the development condition of the apparatus and/or the environmental condition, a judging means for judging the development condition or the environmental condition, a selecting means for selecting the filter condition by referring to the table on the basis of the judged result, and a correcting means for correcting the image formation signal by using the space digital filter of the selected filter condition, whereby the edge highlighting effect is eased.