An investigation on natural environment was carried out. Referring to the natural grade map presented by the Ministry of Environment, the five factors which would be expected to affect the environmental change were examined with multiple regression analysis. The factors above mentioned were as follows : (1) population ; (2) density of road ; (3) altitude ; (4) undulation ; and (5) distance from railway station. These factors are classified into three groups. The first two factors are concerned with the social situation, the next two with the natural situation and the last one is related to the situation of various conveniences of traffic. The proportions of each variate to the natural grade were calculated with the stepwise method. Consequently, it was recognized that the density of road as well as the altitude had the marked effects on the natural grade. With introducing these two variates into the quantitative analysis, the value of 0. 76 was obtained as the multicorrelation coefficient. It is confirmed that the linear multi-regression model is available to analyze the environment of the developing town such as in this case.