A diagnosis support system includes a diagnosis support computer that includes a model data acquisition unit configured to obtain a plurality of mandible model data, a contour model creation unit configured to create contour model data from the mandible model data, a contour database storage unit configured to construct a contour model database from the contour model data, a diagnosis image data receiving unit configured to receive an input of diagnosis image data of an examinee, an edge extraction unit configured to extract edge data from the diagnosis image data, a similar model searching unit configured to search contour model data based on the edge data, a position judgment unit and an image quality judgment unit configured to judge an imaging position and an image quality based on imaging information, respectively, and a diagnosis support information provision unit configured to provide diagnosis support information based on provider information.