PROBLEM TO BE SOLVED: To manufacture a checking prosthetic brace for immediately trially using by adopting a negative pressure particle bag for modeling which can be easily finely regulated in a contact part shape by modeling a site to be modeled in a short time.
SOLUTION: The negative pressure particle bag 10 for modeling comprises a bag outer film 11 made of a low extendible elastic material, and a bag inner film 12 made of a high extendible elastic material and having an upper edge turned up and brought into close contact with the outer film 11. The bag further comprises shape retaining particles 11 filled in an inner cavity formed of the outer film 11 and the inner film 12. An air bag 13 is expanded to be pressed to the site to be modeled. When the cavity is evacuated from a suction nozzle 20, the bag 10 is held in a predetermined shape, and the site to be modeled is modeled.