Total amounts of stem-flow in a deciduous broadleaved forest and a Sugi -Hinoki stand were estimated by measuring the amount of all individual trees in both research sites. Total amounts of stem-flow for the measuring period were 58.9mm and 51.5mm in the deciduous broadleaved forest and the Sugi-Hinoki stand, respectively. The rates of stem-flow to the rainfall at the open area were 3.0% and 3.4%, respectively. In order to estimate easily the amount of stem-flow, the sampling tree method was examined in both forests. The amount of stem-flow was closely related to those of both rainfall and through-fall. The coefficient of linear regression depended on tree size and rainfall. The equations between the amounts of stem-flow and rainfall, through-fall, and tree size（DBH and tree crown projection area）could be obtained by multiple regression analysis. The amounts of stem-flow estimated by using these equations were corresponded to the amount measured directly all individual trees in a deciduous broadleaved forest. However, the amount of stem-flow in a Sugi-Hinoki stand was not enough to estimate because of the low relationship between stem-flow and tree size.