A developer cartridge has: a first body having an opening; a memory unit that has a contact terminal, the memory unit is provided at the first body; and a second body that covers the first body, the second body having a exposure hole; wherein the second body and the first body are movable relative to each other, the second body is able to open and close the opening by a relative movement with regard to the first body, and wherein the contact terminal of the memory faces to outside of the developer cartridge through the exposure hole when the second body is positioned at a first position in which the opening is opened, and the contact terminal of the memory unit is covered with the second body when the second body is positioned at a second position and the opening is closed by the second body.