A map evaluation system is equipped with a car navigation device and a map evaluation device. The car navigation system generates difference data indicating a location where a difference is present between a vehicle position path and a road location obtained from a map database. The car navigation device then sends the difference data along with additional data relating to accuracy of the difference data. The map evaluation device determines accuracy for the difference data based on the additional data. When the accuracy degree of the difference data is determined to be proper, the map evaluation device increments by one a determining count of a group including the difference data. When the determining count exceeds a given count, a portion to be amended on the map database is displayed on a monitor based on the difference data stored in a difference database.