Weather information is acquired and stored from a satellite radio broadcast. On the basis of this weather information, weather information image data is created for displaying the weather information superimposed upon a map. When the weather information display map is scrolled, the range of the map data shifts. Together therewith, the range of the weather information image data also shifts. After a map has been drawn on the basis of the map data for the shifted range, icons or the like that describe the weather information are drawn as superimposed upon this map on the basis of the weather information image data for the shifted range. Then the image data stored in the image memory is read in, and the weather information display map that has been drawn is display upon the display monitor.