In an image processing device, the control device identifies a background color of the image. The control device classifies each of the pixels into either one of a background color pixel group or a non-background color pixel group. The control device determines whether a partial region of the image having the non-background pixel is a chromatic color region or an achromatic color region, without using pixel values corresponding to pixels classified into the background color pixel group. The control device determines that the image is chromatic color image when it is determined that the partial region is the chromatic color region. The control device determines that the image is achromatic color image when it is determined that the partial region is the achromatic color region.