An electronic endoscope processor includes: a converting means for converting each of a plurality of pieces of pixel data that are made up of n (n≥；3) types of color components and constitute a color image of a biological tissue in a body cavity into a piece of pixel data that is made up of m (m≥；2) types of color components, m being smaller than n； a correlation value calculating means for setting a reference axis that is related to a target illness and, for each pixel of the color image, calculating a correlation value with a predetermined reference that is related to the target illness； and an evaluation value calculating means for integrating the correlation values calculated for the pixels and setting a sum of the correlation value obtained by the integrating as an evaluation value that is related to the target illness.
