It makes use of that excellent nature, high purity aluminum is being used as a function material in the electron, the high technology industry and information. Generally that material is molded as a slab, and processed through such as metal rolling is given after that, and it is being made. It is increase demand that it use for condenser. Condenser capacity is increase by making a (100) oriented cube texture crystal. It is known effective to increase a solid solubility of iron to aluminum that make increase the condenser capacity. Therefore, the cooling rate of Al-10,100 and 1000ppm content Fe was controlled by single roller equipment. Research was done about the relations of the amount of solid solubility of iron to aluminum and the cooling rate. It is result that the amount of solid solubility of iron to aluminum becomes 800ppm at the cooling rate of 2×103 K/s. When the cooling rate rises, the amount of solid solubility increases. The change appears in the separation thing as well because the amount of iron changes by this when the cooling rate is high. When iron is solid solubled in aluminum, it is bigger than the case of solid solubility formed by other general metal elements. Hardness is four times rose more than pure aluminum by solid solubility of iron to aluminum about 800ppm.