An example toner cartridge includes a housing to contain toner and having a toner outlet, a conveying member, a shutter to open and close the toner outlet, a driven coupler to rotate the conveying member and having an extension that extends in an axial direction, and a protruding member including a rotational force receiver installed in the extension so as to move to a protruding position in which the rotational force receiver protrudes from the extension and a retracted position in which the rotational force receiver is received into the extension in conjunction with opening and closing operations of the shutter.