Abstract
In the river installed the preventing sand erosion dam in the Miura peninsula, we understood the rise and fall at the season and the egg laying situation of Wrinkled Frog (Rana rugosa) around the breeding time. For the upstream of Morito (800m section) and the Osawadani stream (1,500m section), the watching individual confirmation and the egg batch number confirmation. 354 individuals in total and 133 egg batches were confirmed in the Morito upstream, and 203 individuals in total and 152 egg batches were confirmed in the Osawadani stream. Both are concentrated on a gradual lotic environment, formed on the upstream side of the preventing sand erosion dam. It was guessed that it was an important space for this kind of living and egg laying.