The aims and methods used in this study were the same as in Report 1. This report concerns with the cohort survey on two groups of children who entered primary school in 1971 and 1972 which was continued untill 1977. The results were as follows. 1) The number of examinees were 457 of 1 st grade pupils of primary school in 1971 and 463 of 1st grade pupils of primary school in 1972, 920 children in total. The number of those used in analysing data were 358 and 367, respectively. 2) ΣCx (cumulative number of carious teeth up to the post-eruptive tooth age x-year per initial 100 teeth), Cx (number of teeth newly attacked by caries during the post-eruptive tooth age x-year per initial 100 teeth) and Mx (caries incidence rate of teeth during the post-eruptive tooth age x-year) by kinds of teeth were shown in Table 2.