A navigation device performs a route guidance based on a route from a current location to a destination, the navigation device being connected to a server for searching the route. A navigation method for the navigation device includes sending a request for searching the route to the server and receiving information on the route from the server. The method also includes measuring an elapsed time from a start of the route guidance, and performing the route guidance based on the information received. The method further includes cutting off a communication with the server and coming into a standby state, upon a determination that the elapsed time measured has reached a predetermined time and when the route is being guided or a current location is being checked, to decrease a bandwidth usage between the navigation device and the server and to reduce a communication charge associated with the bandwidth usage.