A toner comprising: a plurality of mother particles; and a plurality of external additive particles to be attached to the mother particles, the external additive particles including external additive particles attached to the mother particle and external additive particles liberated from the mother particles, wherein an inclination (particle sizes of the external additives/particle sizes of the mother particles) of an approximation straight line obtained by approximating distribution of particle sizes of the external additives with respect to the particle sizes of the mother particles by a least-square method is not larger than 0.6. Also, disclosed is an image forming apparatus using the toner.