There is provided a navigation system having a guidance-controller, the guidance-controller controlling the sequence of guidances, and priority, according to an execution condition set depending on the type of a relevant guidance, while determining whether or not a guidance is executed according to the execution condition to thereby alter the teaching of guidance-execution. If overlapping by plural guidances using speech, and screen display occurs, the simple display of the guidance lower in priority is executed, and if the guidance falls outside an effective range, the guidance is interrupted, or the guidance during standby-display is not executed. Thereby, plural guidances are concurrently displayed, and a meaningless guidance is not displayed.