To simplify the operation of a navigation system and to display information regarding a route in such manner that it is easily grasped.

Illuminators 9h and 9v form an infrared-ray lattice plane ahead on a screen 8. Illuminators 10h and 10v form an infrared-ray lattice space ahead of the infrared-ray lattice plane. When a finger is inserted into the lattice space, a coordinate-detecting device 13 detects the coordinate of the fingertip in the space. A CPU 4 measures the distance from the screen 8 to the fingertip based on the coordinate of fingertip, and controls a scale of a display image according to the distance. When the fingertip is moved parallel to the screen 8 in the lattice space, the CPU 4 specifies the advancing direction of the fingertip, based on time-base change of the coordinate of fingertip, so that a display part is moved according to the direction. When the screen 8 is touched with a fingertip, the coordinate of the fingertip is detected on that lattice plane, and the CPU 4 controls so that a display window containing more detailed information about the display part corresponding to the coordinate of fingertip is displayed on the screen 8.