PURPOSE: To produce such a floating body as complex in form inexpensively in cost by installing one bulged part with a gas filler port, and also plural pieces of identical expanded parts being interconnected to this bulged part.

CONSTITUTION: A right part from a fold 5 of a multilayer film 1 folded is a folding part 8, and the fold right part is a nonfolding part 9. A heat seal is applied as linear outline 10, and a parallel straight part 10' serves as a gas filler port 11. A circular part 10" in the nonfolding part 9 is one part of the linear outline 10 turning to one sphere or a bulged part 13, and a circular part 10''' in the folding part 8 is one part of the linear outline 10 turning to two spheres or expanded parts 14, 14. Next, when the excess multilayer film 1 is removed as being cut along the outside of the linear outline 10, a floating body 12 is securable.