A developing agent includes a toner particle containing a binder resin including a first polyester resin synthesized from an aromatic monomer and an aliphatic monomer blended with a molar ratio in an alcohol component being satisfied with the relationship of {(aromatic monomer)>(aliphatic monomer).gtoreq.0} and with a molar ratio in an acid component being satisfied with the relationship of {(aliphatic monomer)>(aromatic monomer)}, a release agent, and a coloring agent.