According to the present invention, a diagnosis support device, which is suitable for comparing different diseases, is provided, along with others. In the diagnosis support device 1 of the present invention, the input of an MRI brain image of a subject is received (step S1), and a shrinkage score, which represents the degree of shrinkage of the brain, is calculated based on the MRI brain image (step S2). Subsequently, sites to be compared in the brain are identified (step S3). Then, a degree of shrinkage, which represents the degree of shrinkage of each of the identified sites, and a shrinkage ratio, which is the ratio between the degrees of shrinkage of the sites, are calculated, and then compared and displayed (step S4).
