When we consider ecological conservation measure, information of plant-pollinated interaction that relate to reproductive of plants is important. Geranium soboliferum Komar. is perennial plant, and habits the midland Japan and part of China and Korea. This species communites have decreased because of land deveropment, etc, and it seems to need artifical help to conserve. So, G. soboliferum has been designed as critically endangered. This study aims to know the composition of pollinaters and the their contribution to breeding success for this plant in Nobeyama Higuland. We investigated distribution of this species by exploration. The survey of pollinator for this species was carried out by observation and sweeping method. And the percentage of fruiti set and flowering phenology were recorded for flowering and fruitiong season in study area. As a result, this plant distributed in more over 16 meshs. So, the habitats seemed to decrease and change according to the Oba’s evaluation method for plant species conservation (Oba 1998). The main pollinators were Halictidae and Apidae. And, the fruit set was from 30 % to 40% for two years. These results showed only annual pattern of pollinator in Nobeyama highland, so, we should conduct continuous reserch with close conditions, additionally.