To enable forming a new view and space which has an organic, warm expression having less strain and is matched with an ambient sight by forming recessed parts by recessing the arbitrary plural parts of the main body of a hollow member made of metal in an arbitrary shape.

Both opening parts of the hollow member 40 to be deformed are closed with sealing covers 43, 44, an evacuating pump 45 is connected to a sealing cover 43, the evacuating pump 45 is operated after filling up a liquid in the hollow member 40 to be deformed and evacuation is executed by discharging the liquid in the hollow member 40 to be deformed. Soft parts are deformed into recessed parts in accordance with the discharge volume of the liquid, the recessed parts 46a, 46b...46k are formed and a deformed hollow member 50 is formed. The soft parts 42a...42o are formed by slowly cooling after heating with a burner, a heater or the like or generating heat by high frequency. Forming the soft parts by chemical treatment or other physical and mechanical processes is considerable. Even when this member is crushed or deformed by impact, it is continuable to use the member as it is.