A navigation apparatus includes: a numerical conversion unit that converts
information related to a specific suggestion to a numerical value; a
suggestion unit that makes the specific suggestion to a user when the
numerical value resulting from numerical conversion executed by the
numerical conversion unit is greater than a threshold value; an input
unit through which a user response to the specific suggestion is input;
and an adjustment unit that changes the threshold value in correspondence
to contents of the user response input through the input unit.