A developer container forming a developing unit of an image forming apparatus, comprising: a container body configured to contain a developer; and a developer delivery member arranged in the container body and configured to rotate so that the developer is delivered, wherein the developer delivery member includes a rotational shaft, a rotating base member configured to rotate together with the rotational shaft, and a body of the developer delivery member configured to be a plate shape, and configured to be fixed to the rotating base member so that the body of the developer delivery member rotates around the rotational shaft; the body of the developer delivery member includes an elastic part having a base-end portion fixed to the rotating base member and a front-end portion rotating along an inner wall of the container body; the container body includes a colliding portion configured to collide with the body of the developer delivery member, a sliding portion configured to be made a sliding contact with the body of the developer delivery member while being curved elastically, a developer delivery chamber in which the body of the developer delivery member rotates toward the colliding portion while being restored elastically, and a developer delivery opening through which the developer is delivered from the developer delivery chamber; the developer delivery opening is open on an upstream side of the colliding portion in a rotation direction of the body of the developer delivery member and an upper portion of the colliding portion faces the developer delivery opening; and the container body and the developer delivery member are configured so that, in a case that the body of the developer delivery member collides with the colliding portion, an air flow to deliver the developer in the container body toward the developer delivery opening is generated characterized in that the colliding portion is formed parallel to a virtual free plane, which is a plane in a case that the body of the developer delivery member is elastically restored to a free state, with a predetermined spacing distance on a downstream side in the rotation direction of the body of the developer delivery member, at a rotating position of the rotating base member at the time of a collision of the body of the developer delivery member with the colliding portion and wherein the predetermined spacing distance is a spacing distance which is smaller than an overshoot amount from the virtual free plane, in the case that the body of the developer delivery member is elastically restored from a curved state. a container body configured to contain a developer; and a developer delivery member arranged in the container body and configured to rotate so that the developer is delivered, wherein the developer delivery member includes a rotational shaft, a rotating base member configured to rotate together with the rotational shaft, and a body of the developer delivery member configured to be a plate shape, and configured to be fixed to the rotating base member so that the body of the developer delivery member rotates around the rotational shaft; the body of the developer delivery member includes an elastic part having a base-end portion fixed to the rotating base member and a front-end portion rotating along an inner wall of the container body; the container body includes a colliding portion configured to collide with the body of the developer delivery member, a sliding portion configured to be made a sliding contact with the body of the developer delivery member while being curved elastically, a developer delivery chamber in which the body of the developer delivery member rotates toward the colliding portion while being restored elastically, and a developer delivery opening through which the developer is delivered from the developer delivery chamber; the developer delivery opening is open on an upstream side of the colliding portion in a rotation direction of the body of the developer delivery member and an upper portion of the colliding portion faces the developer delivery opening; and the container body and the developer delivery member are configured so that, in a case that the body of the developer delivery member collides with the colliding portion, an air flow to deliver the developer in the container body toward the developer delivery opening is generated