There are provided a navigation system, a route search method and a storage medium which are easily capable of setting a destination even if a telephone number, which is not contained in a storage device, is entered. A route search processing unit, in the case where, for example, positions corresponding to telephone numbers that match the number expressing the area of the entered telephone number are four or more, selects four telephone numbers that are approximate to the entered telephone number, and sets the point of intersection, which is formed when the positions corresponding to the selected telephone numbers are connected diagonally by straight lines, as a destination. The route search processing unit searches for a route from the position of a user's car, which is calculated by a vehicle position measuring unit, to a point that is set as a destination.