Real-coded Adaptive Range Genetic Algorithms (ARGAs) have been applied to a practical three-dimensional shape optimization for aerodynamic design of an aircraft wing. The real-coded ARGAs possess both advantages of the binary-coded ARGAs and the floating-point representation to overcome the problems of having a large search space that requires continuous sampling. The results confirm that the real-coded ARGAs consistently find better solutions than the conventional real-coded Genetic Algorithms do.