To provide an imaging system in which an image highlight part can be reproduced stably from a lower density while enhancing resolution and stability for intermediate and high density parts.

The imaging system comprises an optical writing means 100 including at least pulse width modulation in optical modulation, and a gradation processing circuit 78, or the like, at an image processing section comprises means for adding the image data of an adjacent pixel, means for generating a density from a specified pixel based on the added data, means for adding the data of first adjacent number of pixels if the added data is lower than some density and generating a density from a specified pixel based on the added data, and means for adding the data of second number of pixels smaller than the first adjacent number of pixels if the added data is higher than some density and generating a density from a specified pixel based on the added data.