1. A method for managing map data for a vehicle, comprising the steps of: (a) selecting map segments usable for displaying a travel guide map based on a current vehicle location on a display unit, among a predetermined number of map segments which have been loaded on an operation memory to display a travel guide map based on a previous vehicle location on the display unit; (b) designating the map segments selected in step (a) as properties, and remaining map segments as victims; and (c) deleting the map segments designated as the victims in step (b), retrieving remaining map segments required for displaying the travel guide map based on the current vehicle location on the display unit from a physical storage medium with an entire map stored the rein, and updating the operation memory with the retrieved map segments.