The present invention is a method for simultaneously separating two highly pure fullerenes from a mixture of fullerenes via crystallization, by (i) adjusting the amount of solvent in the mixture fed to a first crystallizer to obtain a phase equilibrium behavior so a first fullerene component of the two fullerenes, in the form of pure crystal, solid solution crystal, or solvate crystal is obtained; (ii) adjusting the amount of solvent in another mixture fed to a second crystallizer, operating at a temperature different from the first crystallizer, to obtain a phase equilibrium behavior so a second fullerene component of the two fullerenes, in the form of pure crystal, solid solution crystal, or solvate crystal is obtained; and additionally (iii) purifying the solid solution or the solvate into highly pure fullerene, when the solid product from the crystallizers is in the form of solid solution or solvate.