There is provided a method for manufacturing a double-chamber container (100) including a medical agent storage chamber (61) and a medical solution storage chamber (62) separated from each other by a weak seal portion (30), the method including the steps of: preparing a first sheet-like member (10) including a first medical agent storage chamber forming portion (11) and a first medical solution storage chamber forming portion (12) whose one sides (11A, 12A) are joined to each other, as well as a second sheet-like member (20) including a second medical agent storage chamber forming portion (21) and a second medical solution storage chamber forming portion (22) whose one sides (21A, 22A) are joined to each other； and forming the medical agent storage chamber (61) and the medical solution storage chamber (62) by joining the first sheet-like member (10) and the second sheet-like member (20). The weak seal portion (30) is formed by joining the one side (12A) of the first medical solution storage chamber forming portion (12) and the one side (22A) of the second medical solution storage chamber forming portion (22).
