There is provided a multi-chamber bag that is capable of securely checking a medicinal substance accommodated therein without the necessity to perform a troublesome work, while preventing a matter deteriorating the medicinal substance from reaching the inside of a medicinal-substance accommodation chamber and hence securely preventing the deterioration of the medicinal substance. In a multi-chamber bag having a bag body that has a strong seal part that joins two sheet members together to define an interior space of the bag body, and a weak seal part that partitions the interior space of the bag body into a medicinal-substance accommodation chamber and a medicinal-solution accommodation chamber, a pair of cover sheets are provided to respectively cover the medicinal-substance accommodation chamber. Each of the cover sheets is jointed to the facing sheet member so as to form an outside seal part surrounding the medicinal-substance accommodation chamber. One of the cover sheets has a structure capable of absorbing adverse influence causing matters, and a communication part for communication between spaces formed between both the sheet members and the both the cover sheets is formed between an inside edge of the outside seal part and an inside edge of the strong seal part.本發明提供一種多腔袋,其無須煩雜作業便可確實地進行所收容之藥劑之確認,並且亦可阻止使藥劑劣化之物質到達藥劑收容室內,從而可確實地防止藥劑之劣化。上述多腔袋具備袋本體,該袋本體形成有將兩枚片材彼此接合且劃定內部空間之強密封部、及將片材彼此可剝離地接合且將內部空間分隔為藥劑收容室以及稀釋液收容室之弱密封部,上述多腔袋具備覆蓋藥劑收容室之一對覆蓋片,各覆蓋片接合於形成包圍藥劑收容室之外側密封部之相向之片材,另一方之覆蓋片構成為可吸收劣化因素物質,於外側密封部之內側邊緣與強密封部之內側邊緣之間,形成有使位於兩側之片材與覆蓋片之間的空間連通之連通部。1‧‧‧多腔袋10‧‧‧袋本體11‧‧‧藥劑收容室12‧‧‧稀釋液收容室(藥液收容室)13‧‧‧空室14‧‧‧端口部件20a,20b‧‧‧覆蓋片100‧‧‧內部空間101a,101b‧‧‧片材102‧‧‧強密封部102a,102b‧‧‧第一強密封部102c,102d‧‧‧第二強密封部103‧‧‧第一弱密封部(弱密封部)104‧‧‧第二弱密封部(弱密封部)105‧‧‧連通部105‧‧‧開口(圓孔)200‧‧‧外側密封部
