The present invention provides a developer cartridge capable of appropriately opening/shutting a shutter with simple constitution, and an image forming apparatus. The developer cartridge, including: a container for containing developer; a shutter that is supported so that the shutter can linearly move relative to the container, and that opens and closes by moving linearly; a handle member that is supported so that the handle member can rotationally move relative to the container, and that includes a handle; and a conversion mechanism by which rotational-movement force that rotationally moves the handle member is converted into linear-movement force that linearly moves the shutter.