Developer storage container capable of reducing remaining developer at time of replacement, image forming apparatus

A developer storage container positioned such that a rotation axis of the developer storage container is parallel to a horizontal plane during use, the developer storage container comprising:

• a storage portion configured to convey developer stored inside the storage portion in a conveying direction parallel to the rotation axis by being rotated around the rotation axis in a specific direction;
• a communication portion having a tubular shape that is coaxial to the rotation axis and that extends in the conveying direction from an end of the storage portion on a downstream side in the conveying direction, including an inner peripheral part that gradually increases a diameter in the conveying direction, and connecting the storage portion to an opening portion that has an opening facing the conveying direction;
• and
• a gear portion provided for an outer peripheral part of the communication portion and configured to receive a rotational driving force supplied from an outside, wherein
• the communication portion includes a ridge extending in the inner peripheral part along the rotation axis.