Generally, closely related species cannot coexist, because they usually have competition or sexual conflict each other. However, the distribution areas of the sister land snail species, Ainohelix editha and Ezohelix gainesi (Mollusca, Bradybaenidae), are overlapped widely, despite they are indistinguishable by neutral DNA markers (nuclear DNA ITS-1, 2 and mitochondrial DNA 16S rDNA) and genital morphologies. However, in contradiction to the molecular and genital traits, shell morphology and size show big differences between the two species. We argue that the two groups are nonetheless good species, because the shell size and shape are distinct and often coexist at the same place, and two sympatric species tend to have completely different genotypes. So then, how do they coexist in same place? Or, do they really coexist? In this study, we investigated the microhabitats of these two sympatric species using the line transect method. As a result, no differences were shown between microhabitats of two species (GLMM). This result suggests that there are no or only small biological interactions between two species.