The report storage stores an interpretation report that includes patient-identifying information, examination-specifying information, and medical image-specifying information that specifies medical image data. The image data storage stores the medical image data that includes image data and additional information for the image data that includes the patient-identifying information, the examination-specifying information, and the medical image-specifying information. The key image-searching part specifies an interpretation report that includes patient-identifying information specified by a display request for the medical image data and specifies the medical image data using the medical image-specifying information included in the specified interpretation report. The image data-searching part reads the medical image data from the image data storage based on the additional information of the specified medical image data and the display request. The displaying part displays a medical image based on the read medical image data.