PURPOSE: To decrease the burden on a memory capacity and to make display uniform for a display area possible by executing the processing to evenly arrange characters and displaying the characters on a display board when the total column number of the character patterns after prescribed thinning processing is smaller than the reference column number of the display area.

CONSTITUTION: The data on the character codes and the display area are transmitted via a transmission line 3 from a central control unit 1 and the standard characters or reduced characters are displayed in the corresponding display area from the data on the character codes and the display area. The character font data corresponding to the character codes from the central control unit 1 are called out and the columns blank to the respective character patterns and the columns of the conditions under which the character balance is not significantly changed by the thinning are mainly subjected to the thinning processing. Whether the character patterns after the thinning processing is arrangeable in the display area or not is decided. The processing to evenly arrange the characters is executed in the case where such display is possible. The display is then executed on the display board 2.