An object of the present invention is to perform a more accurate and detailed diagnosis of a brain disease.A diagnosis server 10 of the brain disease diagnosis system 1 for diagnosing a brain disease of an examined person includes: an acquiring unit 11 for acquiring a brain image of the examined person so as to obtain an acquired image a region setting unit 12 for setting a plurality of regions in the acquired image an individual index value calculating unit 13 for calculating an individual index value based on a pixel value of the acquired image, in each of the plurality of regions a whole index value calculating unit 14 for calculating a whole index value by weighting the individual index value of each of the plurality of regions a diagnosis unit 15 for diagnosing the brain disease of the examined person based on the whole index value and an output unit 16 for outputting information indicating a diagnosis outcome.
