Regard to standing bag freestanding suitable for use in medical infusion bag, etc. The present invention is directed to an object of the present invention is to eliminate the risk of bacteria, dust contamination of the sealed. Comprises protrusions 3 in each of the opposed position in diameter [SOLUTION] lip, f1, f2, f3 three circumferential grooves are formed in each of the opposed position in the diameter tubular sheet F. Forming tube 41 to the gusset shape is disposed below the die, forming tube 41 is provided with a molded projection 41-1 conflict diameter of the inner peripheral position, the height of the molded projection 41-1 is low upstream But also, the higher you go on the downstream side, the cross-sectional shape of the molded tube 41 are slowly migrating to the flat shape of the lower end 41b of the upper circular from 41a. That is induced in the fold-smooth to the inverted V-shape by the end of the molding projection 41-1 engages the flutes f1 in the middle of the cylindrical sheet, wrap securely to the flat portion by f2, f3 groove at both ends possible.【課題】本発明は、医療用輸液バッグ等の用途に適した自立型のスタンディングバッグに関し、密閉型の菌・塵埃混入の恐れを解消することを目的とする。【解決手段】リップにおける直径対立位置の各々に3個の突起部を備えており、筒状シートFにおける直径対立位置の各々に3本の縦溝f1, f2, f3が形成される。 ダイの下方にはガゼット形状への成形筒41が配置され、成形筒41は内周の直径対立位置に成形突起41-1を備えており、成形突起41-1の高さは上流側は低いが下流側に行くほど高くなり、また、成形筒41の断面形状は上端41aの円形から下端41bの扁平形状に徐々に移行する。成形突起41-1の先端が筒状シートの中間の縦溝f1に係合することで逆V形状へのスムースな折り込みに誘導され、両端の溝f2, f3 により平面部に確実に折り返すことができる。
