A developer container, comprising: a developer bearing member for bearing a developer, the developer bearing member being configured to convey the developer to an image bearing member; a conveying member which conveys the developer; a frame which stores the developer, the frame including a developer storage chamber which stores the conveying member, a developing chamber in which the developer bearing member is arranged, a partition portion for partitioning the developer storage chamber and the developing chamber, and the partition portion is provided with a first opening which connects the developer storage chamber and the developing chamber with each other and which allows passage of the developer conveyed from the developer storage chamber to the developing chamber, and a second opening which connects an interior of the developing chamber and an exterior of the frame with each other in an orthogonal direction that is orthogonal to a direction of a rotational axis of the conveying member; and a sealing member (24, 25) which suppresses leakage of the developer from between the frame and the developer bearing member; wherein the frame is provided with a plurality of said second openings; and the developer container comprises a filter which allows passage of air and which restricts passage of the developer, the filter being fixed to the frame so as to cover the plurality of said second openings from an outer side of the frame, and the conveying member is deformable such that the developer is conveyed from the developer storage chamber to the developing chamber via the first opening by deformation of the conveying member being released. a developer bearing member for bearing a developer, the developer bearing member being configured to convey the developer to an image bearing member; a conveying member which conveys the developer; a frame which stores the developer, the frame including a developer storage chamber which stores the conveying member, a developing chamber in which the developer bearing member is arranged, a partition portion for partitioning the developer storage chamber and the developing chamber, and the partition portion is provided with a first opening which connects the developer storage chamber and the developing chamber with each other and which allows passage of the developer conveyed from the developer storage chamber to the developing chamber, and a second opening which connects an interior of the developing chamber and an exterior of the frame with each other in an orthogonal direction that is orthogonal to a direction of a rotational axis of the conveying member; and a developer storage chamber which stores the conveying member, a developing chamber in which the developer bearing member is arranged, a partition portion for partitioning the developer storage chamber and the developing chamber, and the partition portion is provided with a first opening which connects the developer storage chamber and the developing chamber with each other and which allows passage of the developer conveyed from the developer storage chamber to the developing chamber, and a second opening which connects an interior of the developing chamber and an exterior of the frame with each other in an orthogonal direction that is orthogonal to a direction of a rotational axis of the conveying member; and a sealing member (24, 25) which suppresses leakage of the developer from between the frame and the developer bearing member; wherein the frame is provided with a plurality of said second openings; and the developer container comprises a filter which allows passage of air and which restricts passage of the developer, the filter being fixed to the frame so as to cover the plurality of said second openings from an outer side of the frame, and the conveying member is deformable such that the developer is conveyed from the developer storage chamber to the developing chamber via the first opening by deformation of the conveying member being released.