A computer aided diagnostic system according to the invention is characterized in that first sick portion detecting means for detecting a sick portion candidate based upon an image acquired by a first modality, second sick portion detecting means for detecting a sick portion candidate based upon an image related to the same region of interest of the same subject and acquired by a second modality different from the modality, detection result synthesizing means for comparing the results of detection by the first and second sick portion detecting means and correspondence displaying means for relating the position of the sick portion candidate detected by the first sick portion detecting means on an image analyzed by the second sick portion detecting means and displaying it and for relating the position of the sick portion candidate detected by the second sick portion detecting means on an image analyzed by the first sick portion detecting means and displaying it are provided. According to the above-mentioned configuration, the computer aided diagnostic system that enables a double check comparing images acquired by plural apparatuses can be provided.
