On-board apparatus

An on-board apparatus includes: a map data storage means in which map data that include altitude information are stored; a subject vehicle position detection means for detecting a subject vehicle position; and a calculation target geographical point setting means for setting a calculation target geographical point 30, 50 based upon the subject vehicle position, wherein a road grade at the calculation target geographical point 30, 50 is calculated based upon altitudes of a plurality of geographical points that include at least a geographical point present ahead of the calculation target geographical point and a geographical point present behind the calculation target geographical point 30, 50.