A developer accommodating unit for accommodating a developer for image formation includes a developer accommodating container including a flexible container provided with openings for permitting discharge of the accommodated developer and sealing member for sealing the openings by a bonding portion and for exposing the openings by being moved, an unsealing member, mounted on the sealing member, for moving the sealing member, and a frame which accommodates the developer accommodating container and the unsealing member and which includes a fixing portion for fixing the flexible container. In addition, connecting potion is disposed between the openings in the flexible container. With respect to an unsealing direction of the sealing member, the fixing portion and the connecting portion are provided so as to overlap with each other.