PURPOSE: To ensure the operation while light weight and environment proof performance are improved by providing a tube and applying a filling agent solidified into a foamed solid to said tube so as to expand and support a structure.

CONSTITUTION: When a control signal 33 is inputted to adjustment sections 23, 24 from a controller, they are opened accordingly to feed a filling agent stored in a filling pressurized vessels 25, 26 to a mixing section 22 respectively. After the mixing part 22 mixes the filling agent at a prescribed rate, a prescribed amount is fed to the tube 20 to be filled and the expanding force attended with foaming of the filling agent and a pressure of a pressure gas expand the tube 20 to expand a folded structure 21. When a prescribed amount of filling agent is fed to the tube 20, the signal 33 is inputted to the adjustment sections 23, 24, which are closed to stop the feed of the filling agent. The foaming of the filling agent is further progressed in the expanding state and the agent is solidified and the foamed body supports the structure 21 in the expanding state while high rigidity and high damping characteristic are given.