PURPOSE: To easily operate graphic input editing well balanced with the text by displaying a grid having lattice intervals depending on a text format on a screen, rounding and correcting while rounding a coordinate value designated by a user within an error range depending on this grid.

CONSTITUTION: The contents of sentences displayed on the editing picture of a display device 5 are divided into areas at need and the number of areas and the information of those areas on a display screen are transmitted. Then, the detected area information is successively received, format information required for preparing the grid of received area is read out, and lattice line information for displaying the lattice lines of the grid is calculated. The coordinates of the start and end points of the calculated lattice line of the grid are successively transmitted to a RAM 3 and stored by areas, and this processing is repeated for all the areas on the screen. As a result, in the case of a display picture example including two areas, the lattice line information is stored in the RAM 3. Then, the coordinates of the start and end points of the stored lattice line information are successively read from the RAM 3 and plotted on the screen by dotted lines, and the lattice line of the grid is displayed.