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.