A navigation apparatus having a hard disk (called HD below) recording and reproduction unit and comprising: a password memory unit that stores a unique first password for each individual navigation apparatus, and that is used when recording data on or reproducing data from a first HD; the HD recording and reproduction unit that performs recording or reproduction by the first password; and a system control unit, which determines whether or not it is possible to use a second password for recording data on or reproducing data from a second HD that is used for updating the data on the first HD, and when it determines that it is possible to do, it updates the data on the first HD with one on the second HD, then it changes the second password to the first password.