PURPOSE: To prevent a side wall type air cushion hydrofoil craft, which is provided with a hydrofoil to control the attitude of the hull, from being subjected to excessive bending force at the hydrofoil mounted portion by giving a level difference especially between a water level in an air cushion room and a water level outside the hull.

CONSTITUTION: In a craft which has an air cushion room 5 between mutually right and left body side walls 3, 3, a hydrofoil 4 located at the lower end of the hull side wall 3 to control the attitude of the hull is formed with the outside portion 4a and the inside portion 4b. The hydrofoil area of the inside portion 4a is formed larger than that of the outside portion 4a or the flap operation angle of the inside portion 4b is controlled greater than that of the outside portion 4a so that the outside portion 4a and the inside portion 4b of the hydrofoil can have almost the same lift, whether there is a level difference between a water level 1 outside the hull and a water level 2 in the air cushion room 5 or not.