Kano's data of nine year follow-up study of Binet Scale were reanalyzed by the method of cluster analysis. The results are: (1) Differentiation of intelligence was generally supported; (2) verbal thinking ability indicated large contribution to intellectual development through nine years, which changed from verbal comprehension ability to concrete verbal reasoning ability to specified formal reasoning ability; (3) memory ability latently differentiated from thinking ability at early periods and more clearly specialized as age advances; (4) memory ability in the early period was highly correlated with verbal thinking ability in the later period, but the verbal thinking ability in the early period did not indicate any high-relation with the memory ability in the later period; (5) developmental stages which corresponded respectively with Piaget's period of preoperational thought, period of concrete operations, and period of formal operations were found.