To provide a portable information terminal device which can display full-color data such as images, pictures, etc., while maintaining small dimensions for its housing and its low power consumption properties.

The contents of a data display process are checked, and the number of display colors used for displaying the data is selected. For instance, if only the character data are to be displayed, only a monochromatic light emission circuit is driven for the display process; but if image data are to be displayed, a plurality of light emitting circuits with different colors are driven for the display process.