To provide a two-layer medical fluid bag that is completely isolated from the outside air to ensure the safety of use, in order to avoid the danger of the invasion of the outside air. A two-layer medical fluid bag (3) comprising an inner wall (31), an outer wall (32), and a puncture device (33), wherein the inner space of the inner wall is used for filling a drug solution, and the outer wall is an inner wall. The interior space, which surrounds the outside of the body at a distance and is formed by the space between the outer wall and the inner wall, is filled with clean air 321 and the puncture device is disposed between the outer wall and the inner wall. During operation, the puncture device is pushed from the outer surface of the outer wall, and the puncture device pierces the inner wall forward, so that clean air enters the inner space of the inner wall and has a pushing effect on the liquid medicine. [Selection diagram] FIG.【課題】外気が侵入する危険を回避するために、外気から完全に隔離され、使用の安全性を確保する二層式医療用流体バッグを提供する。【解決手段】内壁体３１、外壁体３２、および穿刺装置３３で構成される二層式医療用流体バッグ３であり、内壁体の内部空間は薬液を充填するために使用され、外壁体は内壁体の外側を距離を置いて囲み、外壁体と内壁体との間の空間によって形成される内部空間は、清浄空気３２１で満たされており、穿刺装置は、外壁体と内壁体の間に配置され、動作中、穿刺装置は外壁体の外面から押され、穿刺装置は内壁体を前方に突き刺し、清浄空気が内壁体の内部空間に入り込み、薬液に押し込み効果をもたらす。【選択図】図２
