An annotation input section reads from a text file the individual data items constituting an annotation pasted in a specified annotation position on a text as a result of the annotation being inputted from an annotation input window and acquires the input positions of the annotation data items and information on their size. A annotation image magnification change section produces a reduced or enlarged image of the display image of the annotation on the basis of the input positions of the individual annotation data items in the annotation and information on their size acquired by the annotation input section and a specified magnification indicated by a magnification storage section. A text and annotation image display section produces a display image by putting the reduced or enlarged display image of the annotation in the user-specified annotation position on a text display image and displays the display image on the text display screen of a display unit.