In displaying cell images of raised letters under editing on a display screen together with a notation character string corresponding to the cell images, the maximum continuous embossing amount that can be embossed on a single processing sheet when embossing the raised letters on the processing sheet, is predetermined. A continuous embossing amount of the raised letters is determined, and when the continuous embossing amount is in excess of the maximum continuous embossing amount, the excess cell images corresponding to the portion exceeding the maximum continuous embossing amount out of the cell images and the notation character string, or excess notation characters corresponding to the excess cell images are displayed so as to be distinguishable from the remaining portion.