Provided is a multi-chamber bag which enables a user to accurately check a containedmedicine without requiring a complicated work and which can prevent a materialwhich degrades the medicine from reaching the medicine containing chamber andsurely prevent degradation of the medicine. The multi-chamber bag includesa bag body having a strong seal portion and a weak seal portion. The strong sealportion has two sheet members bonded to each other to partition an internal space. The weak seal portion has sheet members detachably bonded to partition the internalspace into a medicine containing chamber and a dilution liquid containing chamber. The multi-chamber bag includes a pair of cover sheets which cover the medicinecontaining chamber. Each of the cover sheets is bonded to an opposing sheet memberforming an external seal portion surrounding the medicine containing chamber. The other cover sheet is configured so as to absorb a bad material. A communicationportion is formed between the inner side edge of the outer seal unit and the innerside edge of the strong seal portion so as to communicate with the space betweenthe sheet member and the cover sheet at the both ends.
