PURPOSE: To effectively reduce resistance of a wing in the main wing or the like of an aircraft without using power.

CONSTITUTION: An opening part is provided in an end of a wing 2, to serve as a draft port 3, and it is connected through a pipe 4 to pressure adjusting chambers 5 in the wing 2, to connect the pressure adjusting chamber 5 to suction ports 6 of hole opened in a shell of the wing 2. A turbulent fluid around the wing 2, via the pressure adjusting chamber 5, is sucked toward the draft port 3 in the wing end at a low static pressure and discharged from the draft port 3, so as to reduce resistance of the wing 2.