PURPOSE: To change a vertical stabilizer to the optimum fitting angle according to flight conditions by fitting the lower end section of the vertical stabilizer to an airframe rotatably around the axis nearly parallel with the vertical axis of the airframe.

CONSTITUTION: The lower end section of a vertical stabilizer 2 is fitted to an airframe 1 rotatably around the axis nearly parallel with the vertical axis in the longitudinal direction of the airframe 1. The vertical stabilizer 2 is rotated to change its fitting angle according to the flight conditions such as the elevation angle and speed of an aircraft, and the optimum effective position of the vertical stabilizer 2 can be provided. The vertical stabilizer 2 itself can be minimized due to its efficiency, radar invisibility can be improved, and drag and airframe height can be reduced.