An inverse design method that treats multiple wings (or multi components of a wing) is examined from the viewpoint of the effect of interaction among wings on a designed section shape. This new method has been devised recently on the basis of Takanashi's integral equation method. It takes into consideration the mutual interaction among wings to provide section shapes of wings which realize a specified surface pressure distribution. This method works well on several preliminary design problems. It is found that both of aerodynamic mutual interaction and the correlation between the geometrical change of a certain wing and that of the others should be considered for efficient and accurate design.