A toner for developing electrostatic images, comprising colored resin particles that contain a binder resin, a colorant and a charge control agent, and external additives, wherein the external additives contain at least an external additive A and an external additive B; wherein the external additive A is metal oxide particles charged to the same polarity as a polarity of the colored resin particles, with a specific charge amount per unit surface area and a specific number average particle diameter; wherein the external additive B is resin particles charged to the opposite polarity to the polarity of the colored resin particles, with a specific number average particle diameter; and wherein a content of the external additive A and a content of the external additive B are in specific ranges.