Recently, the population of Rana porosa brevipoda has been decreasing and disappearing from previously observed habitats. Although emergency conservation measures for this species have to take action, the ecological information of this species is critically lacking. Among them, a food habit is particularly important for this frog survival. The purpose of this study is to know the relationship between the food habits of this frog and environmental conditions in the Ina Basin, Nagano Prefecture by forced regurgitation of stomach contents. For diet analyses, we collected R. p. brevipoda in 6 paddy fields, where were different of the surrounding land use. We also collected potential prey arthropods on the grassy bank by sweeping method. The surveys were carried out for two years. The frog diet consisted of a wide variety of arthropods, caterpillars, beetles, ants, dipterans, and spiders, which were especially dominant. However, other arthropod taxa were mainly collected by sweeping method. These results were common in each area. As a result of using DCA, the main factors determining food habit were the body size and orthopteran population. Therefore, we estimated that food habit of this frog was not strongly influenced by regional difference rather than the body size.