An image determination apparatus, an image reading apparatus, and an image determining method include a device for cutting a color/monochrome region based on a color saturation value obtained by a predetermined derivation method based on image data, and a device for detecting image errors located in large boundaries of brightness variations including color distortions based on correlations between color saturation and color. When errors are included in the image data acquired by, for example, a color image scanner due to primary color errors at random locations (in particular, color bleeding that occurs as a color distortion in monochrome achromatic color areas), it is possible to extract characteristics from the image data and detect locations in images where color distortions and color bleeding occur without using especially complicated and special compositions to detect where these errors occurred.