A developer container, comprising: a container body including an inner circumferential surface defining a cylindrical internal space extending in a first direction, a wall part defining one end surface of the internal space in the first direction, and an opening disposed at the other end surface of the internal space opposite to the wall part in the first direction, and the container body formed with a developer discharge port in one end portion of the container body to communicate with the internal space and discharge developer therethrough, the developer discharge port being closer to the wall part than to the opening in the first direction; a lid mounted on the container body to cover the opening; a movable wall including an outer circumferential surface slidable over and in close contact with the inner circumferential surface of the container body, and a conveying surface defining a storage space for the developer in cooperation with the inner circumferential surface and the wall part of the container body, the movable wall being movable in the internal space in the first direction from an initial position closer to the lid of the container body to a terminal position closer to the wall part while conveying the developer in the storage space to the developer discharge port; a shaft including a first engaging portion in the form of a helical ridge in an outer circumferential surface thereof, extending in the first direction in the internal space, and one end and the other end of the shaft being supported on the wall part and the lid rotatably; a bearing portion disposed on the movable wall for allowing the shaft to be inserted, and including a second engaging portion on an inner circumferential surface thereof and engaging with the first engaging portion; a torque transfer section for transferring a torque to the shaft; a projecting wall that is a portion of an outer circumferential portion of the container body projecting to outside relative to the wall part in the first direction; a cover mounted on the projecting wall; and a sealing member; wherein the wall part has a developer filling port penetrating the wall part in the first direction and communicating with the storage space, when the shaft is rotated, owing to the engagement of the first engaging portion and the second engaging portion, the movable wall moves along the shaft in the first direction, and the sealing member seals the developer filling port. a container body including an inner circumferential surface defining a cylindrical internal space extending in a first direction, a wall part defining one end surface of the internal space in the first direction, and an opening disposed at the other end surface of the internal space opposite to the wall part in the first direction, and the container body formed with a developer discharge port in one end portion of the container body to communicate with the internal space and discharge developer therethrough, the developer discharge port being closer to the wall part than to the opening in the first direction; a lid mounted on the container body to cover the opening; a movable wall including an outer circumferential surface slidable over and in close contact with the inner circumferential surface of the container body, and a conveying surface defining a storage space for the developer in cooperation with the inner circumferential surface and the wall part of the container body, the movable wall being movable in the internal space in the first direction from an initial position closer to the lid of the container body to a terminal position closer to the wall part while conveying the developer in the storage space to the developer discharge port; a shaft including a first engaging portion in the form of a helical ridge in an outer circumferential surface thereof, extending in the first direction in the internal space, and one end and the other end of the shaft being supported on the wall part and the lid rotatably; a bearing portion disposed on the movable wall for allowing the shaft to be inserted, and including a second engaging portion on an inner circumferential surface thereof and engaging with the first engaging portion; a torque transfer section for transferring a torque to the shaft; a projecting wall that is a portion of an outer circumferential portion of the container body projecting to outside relative to the wall part in the first direction; a cover mounted on the projecting wall; and a sealing member; wherein the wall part has a developer filling port penetrating the wall part in the first direction and communicating with the storage space, when the shaft is rotated, owing to the engagement of the first engaging portion and the second engaging portion, the movable wall moves along the shaft in the first direction, and the sealing member seals the developer filling port.