PURPOSE: To secure the directional stability and safety of an aircraft by forming the side face shape of a vertical tail approximately into L-shape, and protruding the longitudinal side of the L-shape onto the airframe during normal flight while protruding the lateral side of the L-shape below the airframe at the time of high incidence angle flight.

CONSTITUTION: An aircraft 3 is provided with a vertical tail 1, its rotating device 2, rudders 4 disposed on the respective opposed inner sides of the longitudinal wing 1a and lateral wing 1b of the vertical tail 1, and a horizontal tail 6 added to an after fuselage 5. The side face shape of the vertical tail 1 is formed approximately into L-shape. The rotating device 2 pivotally supports the vertical tail 1 so as to be rotatable near the corner between the longitudinal wing 1a corresponding to the longitudinal side of the L-shape and the lateral wing 1b corresponding to the lateral side of the L-shape, parallel to the pitch shaft (lateral shaft) of the aircraft 3 and within a range of from the state of the longitudinal wing 1a protruding onto the after fuselage 5 to the state of the lateral wing 1b protruding below the after fuselage 5. The vertical tail 1 is thereby positioned outside of fuselage back wash so as to secure directional stability at the high incidence angle time.