To provide a wind tunnel simulation device for improving efficiency in designing by a wind tunnel test and a method for designing an airframe using the device.

A wind tunnel simulation device is provided with a model airframe-supporting device comprising a model support robot 20, a model support sting 30 and the like so that the attitude of a model airframe 60 can be supported in a wind tunnel 10, a balance 65 for measuring each load in X, Y, and Z axes that acts on the model airframe 60 and each moment around X, Y, and Z axes an attitude angle sensor 66 for measuring the pitch angle, roll angle, and yaw angle of the model airframe 60, and a control device 50 which calculates the position and attitude angle of the model airframe 60 after a specific time based on the load and each movement measured by the balance 65 and each attitude angle measured by the attitude angle sensor 66, and gives instruction to the model airframe-supporting device for changing the attitude of the model airframe 60 to the calculated position and the attitude angle.