1. An icon display apparatus comprising: display means for displaying a picture including a window having an iconifying designation mark, a plurality of icons, and a cursor having a shape; input means for moving the cursor to the iconifying designation mark and designating the iconifying designation mark; iconifying designation detecting means for detecting the iconifying designation in response to the designation of the iconifying designation mark; window display coordinate storing means for storing a window name and display coordinates of the window, a display order, an iconifying flag representing whether an iconifying state is set, and icon display coordinates; means for reading out the window name and display coordinates thereof in a display order from said window display coordinate storing means in response to the direction of iconifying designation by said iconifying designation detecting means; an icon image memory for storing a plurality of icon data corresponding to the plurality of icons and outputting icon data corresponding to the window name read out from said window display coordinate storing means; window erasing means for setting the iconifying flag and erasing the display order stored in said window display coordinate storing means upon the detection of the iconifying designation from said iconifying designation detecting means; cursor changing means for changing the shape of the cursor from a first shape to an icon frame shape which is different from an icon shape in response to the iconifying designation from said iconifying designation means and for restoring the shape of the cursor from the icon frame shape to the first shape at a location selected by user; and means for supplying the icon data corresponding to the window name, the icon data being read out from said icon image memory, and the icon display coordinates to said display means.