A container for developer detachably mountable to an image forming apparatus body includes a rotating body that contains developer and is rotated about a rotational center when drive is transmitted from the apparatus body, a discharge member that supports the rotating body such that the rotating body is rotatable relative to the discharge member and has a discharge port through which the developer is discharged, an anti-leakage member that is disposed in one of the rotating body and the discharge member and suppresses leakage of the developer, and a compressing portion that has a first side and a second side farther from the rotational center than the first side, is disposed in the other of both, and is pressed against the anti-leakage member to compress the anti-leakage member such that a compressing amount is larger on the second side than on the first side.