<p>Provided is a cartridge into which a developer can be refilled without damaging the filling opening or the cap while allowing the developer refill history to be checked easily by using inexpensive components. This developing cartridge (19) comprises: a developing frame (25) in which a filling opening (46) is formed; and a cap (57) having a hole (67). The developing frame (25) is provided with: a cylindrical part (51) that protrudes to the outside of the developing frame (25) so as to surround the filling opening (46); and a protruding part (53) that is arranged more to the outside than the cylindrical part (51) and that is to be fixed with the hole (67). The cap (57) is fixed to the developing frame (25) by irreversibly deforming the hole (67) and the protruding part (53).</p>
