There is provided a processor device for an endoscope capable of acquiring a blood vessel index value of a specific observation distance used for predetermined diagnostic criteria. A distance acquisition unit acquires a non-magnified observation distance at the start of the change of the imaging magnification, and acquires magnified observation distance at the end of the change of the imaging magnification. A distance ratio calculation unit calculates a first distance ratio between the non-magnified observation distance and the magnified observation distance. A blood vessel index value calculation unit calculates a blood vessel index value of the non-magnified observation distance from the image signal acquired at the non-magnified observation distance. An index value correction unit corrects the blood vessel index value of the non-magnified observation distance according to the first distance ratio to acquire a blood vessel index value of the magnified observation distance.
