An electrophotographic apparatus reproduces a picture by expressing a gradation of the picture by use of halftone spots which are each formed by dot pictures within a plurality of pixels. The electrophotographic apparatus has a picture reproducing engine for forming the dot pictures by attaching toner to virtual dot areas each within the pixel, and an image processing unit for causing (i) growth of halftone spots of a first group in a first data range of input image data to increase a gradation of the dot pictures, and (ii) growth of halftone spots or a second group in a second data range of the input image data, which is adjacent to higher gradation level side of the first data range to further increase the gradation of the dot pictures. The gradation of the dot pictures is simply increased by the image processing unit without decrease at a boundary between the first and second data ranges.