An external addition toner that sufficiently exhibits the effect of an external additive and is excellent in transfer property, and an apparatus for forming an image and a process for forming an image excellent in general purpose property that provide an image of good quality without formation of image defects, such as transfer unevenness and drop off due to transfer failure of the toner. An external addition toner is employed, in which the shape coefficient of the toner particles, as well as a coating ratio x (%) of the external additive to a surface area of the toner particles, a volume average particle diameter D (&mgr;m) of the toner particles and a volume average particle diameter d (&mgr;m) of the external additive having the maximum average particle diameter satisfy the prescribed relationship. Furthermore, a developer is employed, which contains a toner charged to a charge amount q (&mgr;C/g) satisfying the following equation corresponding to the volume average particle diameter D (&mgr;m) of the toner particles: q≧929.5/D2