Provided is a two-component developer with which degradation of development is inhibited even in the case of prolonged use, and thereby a high quality image exhibiting high resolution and sufficient image density can be formed for a long duration. Also disclosed is a two-component developer possessing a carrier and a toner, wherein the carrier in which magnetic material powder is dispersed in a binder resin containing a phenol formaldehyde resin has a shape coefficient SF-1 of 1.0-1.2, a shape coefficient SF-2 of 1.1-2.5 and a volume-based median particle diameter of 10-100 μm, and the toner possesses a colored particle and an external additive particle, wherein the external additive particle comprises a titanic acid compound and iron, and the iron content is 100-1,000 ppm, based on the titanic acid compound.