A cartridge, comprising: a developing roller configured to rotate around a first rotational axis extending in a predetermined direction and to carry developer thereon, the developing roller having a first end and a second end that are apart from each other in the predetermined direction, a from-first-to-second direction being defined along the predetermined direction as being directed from the first end to the second end; a developing electrode formed of a conductive material and configured to be electrically connected to the developing roller, the developing electrode including a main part and a protruding portion that protrudes from the main part in the from-first-to-second direction, wherein the protruding portion is configured to be supplied with electric power from outside; and a detection body, wherein the detection body is configured to move relative to the protruding portion from a first position through a second position to a third position, the first, second, and third positions being different from one another characterized in that the detection body is rotatably supported by the protruding portion, the detection body including a first opening that exposes part of the protruding portion and a covering portion (95, 136) configured to cover part of the protruding portion, the detection body located at the first position allowing the protruding portion to be supplied with electric power via the first opening, the detection body located at the second position preventing the protruding portion from being supplied with electric power by the covering portion, and the detection body located at the third position allowing the protruding portion to be supplied with electric power via the first opening. a developing roller configured to rotate around a first rotational axis extending in a predetermined direction and to carry developer thereon, the developing roller having a first end and a second end that are apart from each other in the predetermined direction, a from-first-to-second direction being defined along the predetermined direction as being directed from the first end to the second end; a developing electrode formed of a conductive material and configured to be electrically connected to the developing roller, the developing electrode including a main part and a protruding portion that protrudes from the main part in the from-first-to-second direction, wherein the protruding portion is configured to be supplied with electric power from outside; and a detection body, wherein the detection body is configured to move relative to the protruding portion from a first position through a second position to a third position, the first, second, and third positions being different from one another characterized in that the detection body is rotatably supported by the protruding portion, the detection body including a first opening that exposes part of the protruding portion and a covering portion (95, 136) configured to cover part of the protruding portion, the detection body located at the first position allowing the protruding portion to be supplied with electric power via the first opening, the detection body located at the second position preventing the protruding portion from being supplied with electric power by the covering portion, and the detection body located at the third position allowing the protruding portion to be supplied with electric power via the first opening.