To provide such information as the traffic information, etc., from the map information on the present location of a vehicle and its surrounding area without spoiling effective information.

The map indicating the present location of its own vehicle and its surrounding area is displayed on a display device (100) and, when VICS information is received (102), the displaying amount of information indicating the total amount of map information to be displayed is computed (106 and 107). When the computed amount is small ('No' at 108), the VICS information, etc., is displayed by superimposing the information on the map for a prescribed period of time (116 and 118). When the computed amount of map information is large ('Yes' at 108), on the other hand, the essence contained in the map information are extracted (110) and the VICS information, etc., is displayed, and then, the essence extracted from the map information by deforming the map information are displayed in the deformed state for a prescribed period of time (112 and 114).