PURPOSE: To confirm the conditions of a file without opening an area indicated by an icon by taking out the icon of a shape corresponding to a tile amount obtained for each prescribed group from a correspondence table and displaying it.

CONSTITUTION: An auxiliary storage device 5 stores an icon display information table 9 for which the predetermined file amount and the shape of the icon are made correspond to each other. Then, the file amount of the predetermined group is obtained for each group by a data processor 6, the icon of the shape corresponding to the obtained file amount is taken out from the icon display information table 9 stored in the auxiliary storage device 5 by the data processor 6 and the taken-out icon is displayed on a display device 8. Thus, without opening the icon, the amount of the file can be judged by the shape (or color) of the icon.