Navigation system and navigation method

This invention relates to a navigation system comprising an information distributing center including a route data creating unit that, when having received a route calculation condition including at least a departure point and a destination from a navigation device, calculates a guidance route from the departure point to the destination and creates guidance route data, and a distributing unit that distributes the guidance route data to the navigation device; and a navigation device including a route guidance unit that, when having received the guidance route data, provides route guidance based on the guidance route data, a current position detecting unit that detects a current position, a deviation determining unit that determines whether the current position has deviated from the guidance route, and a recalculation condition transmitting unit that, when it has been determined that the current position has deviated from the guidance route, transmits to the information distributing center a reroute calculation condition including the current position and the destination.