An in-vehicle navigation apparatus is equipped with (i) an HDD for recording map data for display and, further, (ii) an external memory, which is not an HDD and in which the map data recorded in the HDD can be copied. The navigation apparatus performs the following: when the main power is supplied to the map display device, the altitude of the position of the vehicle (startup altitude) is specified; when the specified startup altitude is equal to or higher than a reference altitude, the map data are read from the external memory and the corresponding map is thereby displayed on an image display device, with the HDD not activated; and when the specified startup altitude is lower than the reference altitude, the map data are read from the HDD and the corresponding map is thereby displayed on the image display device.