PURPOSE: To easily fly a large kite on the sea by providing floating beds supporting the large kite afloat on the water surface, and connecting the other end of a main rope connected to the large kite at one end to a winch mounted on a towing boat having the propelling power.

CONSTITUTION: A large kite 1 is formed with skeletons 6 and a water-resistant sheet material 7 stretched on their surfaces into a square shape as a whole, it is towed on the sea while it is mounted on floating beds 2, and the large kite 1 is obliquely supported in the rising gradient state upward. One end of a main rope 3 is connected to the large kite 1, and the other end of the main rope 3 is connected to a winch 4 mounted on a towing boat 5. To fly the large kite 1, the towing boat 5 is cruised at a high speed, and the large kite 1 is towed at a high speed via the main rope 3. The large kite 1 is lifted by the floating force applied to the large kite 1, and the large kite 1 is flown high in the air when the main rope 3 is delivered from the winch 4 in sequence.