There is provided an image discriminating apparatus for discriminating the type of an image accurately. The apparatus compares a maximum value R among absolute values of mutual differential values of three color components of each pixel composing an image, with two predefined threshold values &bgr; and &ggr;, respectively, and counts numbers C1-C3 of the monochrome pixels, medium pixels and color pixels, respectively, on the basis of the comparison result for each line within the image. The apparatus judges each line within the image as a color line when C3+C2×&ohgr;>&thgr;, as a monochrome line when Cl>&ngr;, and judges the image as a color image when a number of color lines in the whole image exceeds a threshold value. The second apparatus compares maximum and minimum values of the absolute values of each pixel with three threshold values to judge whether each pixel is a color, medium, ground or monochrome pixel and increments counter values of color, medium and monochrome pixel counters according to the range of each discriminated pixel. When the number of continuous monochrome pixels exceeds a threshold value within the image, the apparatus corrects the three counters and discriminates the type of the image based on the three counters after the correction.