To provide an air jack having an improved jack function, having no horizontal shift when inflating an airbag, thereby concentrating its inflating pressure in the floating direction of an automobile.

A load supporting frame 6 in a lower-face opening having a load supporting portion 1 for supporting a jack point (a) provided on the lower face of the automobile, a base frame 5 in an upper-face opening, and intermediate frames 9, 8, 7 laid between both frames are combined together in the state of putting an outward protruded portion piece provided at the lower end of the cylindrical body of the upper-side frame on the lower side of an inward protruded portion piece provided at the upper end of a cylindrical body of the lower-side frame, to form a flexible body 4. The foldable airbag 3 is locked to the bottom plate of the base frame 5 on the lowermost side of the flexible body 4 and stored in the flexible body. It is locked to the lower faces of the outward protruded portion pieces of the load supporting frame and the intermediate frames. An nozzle 2 for filling the airbag 3 with air is supported on the load supporting frame or the base frame.