Drive support device, drive support method and computer program

The invention provides a drive support device capable of preventing the drive support with error content even when a vehicle is in a retrograde condition, a drive support method and a computer program. A match process of a position match of the vehicle detected by such as a sensor on the road is repeatedly performed in a predetermined interval and various drive support processes are performed based on the matched position of the vehicle. On the other aspect, it is detected whether the vehicle is in the retrograde condition or not and if the vehicle is detected to be in the retrograde condition, the performing of the match process (S3) is stopped.