Similar medical images having a predetermined similarity to a region of interest in a medical image to be interpreted are received from a case search system. A display screen on which the received similar medical images are displayed is displayed on a display. The display screen includes display frames within which similar medical images are displayed. In response to an instruction for enlarging the similar medical images, corresponding regions of interest in the similar medical images are enlarged and displayed with the sizes of the display frames maintained unchanged on the display screen. In response to an instruction for causing a selected similar medical image among the enlarged and displayed similar medical images to move within a corresponding display frame, the other unselected similar medical image(s) is caused to move within a corresponding display frame synchronously with the movement of the selected similar medical image in the same movement direction.