A developer cartridge has a rotatable body, a casing, a conveying guide structure, and a cover. The cover includes a facing part and a first covering part. The conveying guide structure includes a first conveying guide extending in the second direction, and a second conveying guide connected from the first conveying guide at an end on the other side of the second direction and extends toward the other side of the second direction so as to curve in the first direction with respect to the first conveying guide. The first covering part includes a first contacting part configured to contact the first conveying guide, and a second contacting part configured to curve in the first direction with respect to the first contacting part so as to extend toward the other side in the second direction, and contact the second conveying guide.