1. A route search method for a navigation device, wherein the navigation device includes a storage device which stores map data including link data of respective links constituting roads on a map, and statistical data including travel time or moving speeds of the respective links determined by statistical values of traffic information collected in the past, said statistical data being classified every condition of collection of the traffic information, and the route search method comprises: setting step which sets a departure position, a destination, and conditions of collection; and recommended route searching step which searches a recommended route from the departure position to the destination, by using the map data stored in the storage device and statistical data corresponding to the conditions of collection set in the setting step out of the statistical data stored in the storage device.