The present invention concerns a VTOL (Vertical Takeoff and Landing) aircraft. The VTOL aircraft generates lift through a helicopter-shaped rotor when taking off, then flies forward. For further efficient flight at middle or low speed, the VTOL aircraft generates thrust in order to propel the fuselage by a propeller engine which is mounted on the center of the main wing or the fuselage. In addition, the VTOL aircraft can fly forward while generating rearward thrust to help propel the fuselage by turning by 90 degrees the rotors mounted on both sides of the main wings toward the flying direction.