Navigation system and navigation method for moveable body, and computer program

A navigation system for a movable body is provided with: a current position detection device (2, 10, 18, 20) for detecting a current position of a movable body; a map information presentation device (3, 20) for presenting map information corresponding to the detected current position; a route condition information presentation device (4, 20) for presenting route condition information indicating a current condition of a route on which the movable body is driving; and a driving route presentation device (6, 20) for performing a presentation indicating that the movable body can overtake, in case that the movable body on the route can overtake on the basis of the presented map information and the presented route condition information.