A numerical method is proposed for analyzing the potential flow around a lifting body such as a wing, a rudder, and a propeller. The method is different from the panel method in which boundary surface of the lifting body is divided into panels. In the present method the boundary surface is treated as continuous surface and the unknown (potential on the surface) is also expressed as the continuous function. So we call the method “continuous method”. In the method the boundary integral equation is solved as accurately as necessary for the purpose using automatic numerical integration routine. Numerical results by the present method are compared with the analytical solution in case of a sphere, an ellipsoid, and a Kármán-Trefftz aerofoil. The comparison shows the accuracy of the method. Finally numerical results are shown for a circular wing and the results are compared with other methods such as the panel method and the lifting surface method, and also compared with experimental results. Those comparisons show the validity of the present method.