In planning river training project, it is a matter of importance to clarify the chara cteristics of rainstorm. Some properties of rainstorm were investigated by statistical method in this study. The rainfall data containing one-day storm over 100 mm for a period of 33 years at Matsue were assorted into three types ; which are bai-u front storm, typhoon storm and other front storms. The differences of characteristics in each type explained by comparison of various factors of which storms are composed, are as follows :
(1) Regarding the mean value of period T from the beginning of storm to the end, the value of typhoon type is greater than those of other types, and the front type has a minimum value.
(2) In three type storms, the mean values of sum of one-hour rainfall within a certain range, are different respectively. The front type has more one-hour rainfall over 30 mm than other types, while the typhoon type has most one within 5 mm.
(3) In all types, the sum of one-hour rainfall within 5 mm nearly corresponds to the period T of each type.