A sheet feeding device includes a container including a frame, an auxiliary frame member provided on the frame so as to be slidable relative to the frame, and a front cover that covers a front side of the auxiliary frame member, the container being detachably supported in a body of the sheet feeding device; a cover member that covers a top side of the container when the container is attached to the body; and a locking unit that prevents the container attached to the body from being detached from the body when the container is locked and that enables the container to be detached from the body when the container is not locked.