PURPOSE: To attain a high resolution display of a large amount of graphic data using a normal standard CRT device by combining the normal standard CRT and an exclusive display controller.

CONSTITUTION: The display controller is provided with a graphic memory 11, a CRT controller and shift register, etc. The vertical scan of the CRT controller can be specified for a noninterlace system or an interlace system, a screen display starting position can be specified at least in the vertical direction and a cursor control function is provided. Moreover, normal standard horizontal dots, horizontal bits whose number is larger than the number of vertical lines and a vertical bit graphic memory 11 are provided. A screen S is used to display by selecting an interlace system screen corresponding to the whole region of the memory 11 and a noninterlace system screen corresponding to a partial region. The latter screen is scrolled in the vertical direction.