PURPOSE: To display part of display data separately from other ordinary display data, by using a false half-luminance display pattern obtained from the AND process of a pattern used for ordinary display and a netting pattern.

CONSTITUTION: When power supply is made, the display device of this invention starts the operation as a display device in accordance with a program in an ROM5. When a thrown-in command is a false half-luminance display command, the display device executes an instructed false half-luminance display process. Namely, the display device reads the pattern of display character data and a netting pattern for generating a false half-luminance display pattern from a character generator 2. Then the device obtains the AND of the pattern of the character data and netting pattern and generates a data pattern for displaying a false half-luminance. When this process is terminated, the device calculates an address in an picture video memory 8, at which the false half-luminance displaying data pattern is written and writes the image pattern of the generated pattern in the picture video memory 8. Therefore, the false half-luminance display pattern is displayed on a CRT9.