An image-forming device includes a body, a developer cartridge, a first detecting unit, a second detecting unit and a controller. The developer cartridge accommodates developer therein and is detachable from the body. The developer cartridge includes an information member disposed, when the developer cartridge is mounted on the body, in at least one of a first position and a second position different from the first position in accordance with information with respect to the developer cartridge. The first detecting unit detects that the information member is disposed at the first position. The second detecting unit detects that the information member is disposed at the second position. The controller determines the information with respect to the developer cartridge based on the detecting result of at least one of the first detecting unit and the second detecting unit.