PURPOSE: To compensate also past position display by utilizing map matching treatment.

CONSTITUTION: A position display means 5 superimposes the position on a road near a current position which is determined by a driving locus obtained by using a vehicle speed sensor 3 and an azimuth sensor 2 according to the initial position which is input by a position input part 7 for a certain time interval or a driving interval and then displays it on a display 6. After that, the position display means 5 performs map maching treatment with a specific interval extracts a current position and a past driving link, and then erases the position display at the display 6. Then, the extracted link is traced, positions are obtained for each certain distance, and then they are displayed at the display 6.