A storage device of a report producing terminal stores an importance table. The importance table stores grades of importance of respective items of accessory information on medical images. Prior to displaying a medical image on a screen, an area defining section extracts a main subject display area of the medical image, and defines an accessory information display area outside the main subject display area. A display style defining section calculates a necessary display area for each individual item of the accessory information, and discriminates between those items which fit in the accessory information display area and those which do not. The display style defining section decides not to display the items which do not fit in the accessory information display area, or decides to display them in a transparent style, in a scrolling style, in a switching style or with a small font.