To provide a data updating system and the like for easily performing updating the difference for the database which contains a large amount of data, each piece of the data being highly correlated, such as a map database that contains road network data.According to the present invention, the data updating system includes a terminal device running according to a predefined operating program, and servers providing the terminal device with a differential data file for updating a database. The terminal includes a local database in an updating data format differing from a reference data format to be referenced to by the operating program and being updated with the differential data file, and a conversion means converting data stored in the local database so as to have the reference data format. The servers include a differential data file output means outputting the differential data file to be provided to the terminal device.