A developer container includes: a developer accommodating chamber, provided with an opening, for accommodating a developer; a sealing member including end portion sealing portions each for sealing an end portion of the opening and a central portion sealing portion for sealing a central portion of the opening; and a rotatable member, connected with the sealing member, for peeling off the sealing member from the opening by rotation thereof to expose the opening. With respect to a rotational axis direction of the rotatable member, an outer configuration of the rotatable member is different between a sealing-member-connected end thereof and a sealing-member-connected center thereof so that one of the end portion sealing portions is peeled earlier than the central portion sealing portion and so that the central portion is peeled earlier than the other one of the end portion sealing portions.