A vehicle navigation system includes a hard disk drive, which stores an old navigation software set; an optical disk drive which is accessible to an optical disk which stores a new navigation software set; a first executing section which drives the hard disk drive; and a second executing section which drives the optical disk drive. An install section responds to a navigation instruction to control the first executing section to drive the hard disk drive such that a vehicle navigation is carried out based on the old navigation software set, when the optical disk is not available. Also, the install section controls the second executing section to drive the optical disk drive such that the vehicle navigation is carried out based on the new navigation software set and the first and second executing sections to drive the hard disk drive and the optical disk drive such that the new navigation software set is installed from the optical disk into the hard disk drive, when the optical disk is available.