This paper deals with a leader-following formation navigation (LFFN), which is one of the most important issues in formation control. In this formation, one leader is controlled by a human operator, while multiple followers pass along the leader's trajectory in the same motion to the leader. The followers move along the leader's path behind the leader after some intervals. In this navigation method, the distances between the robots are not considered, thus some of the followers are possibly too late to maintain the formation. This paper proposes a new LFFN method with the maintenance of the formation-distances. The proposed method minimizes the sum of the evaluation functions concerning the velocity and distance errors. The effectiveness of the presented method is demonstrated by an experiment with three mobile robots.