Using the Ochiai District of Higashiiyayama Village in Tokushima Prefecture, this paper discusses how the plans of farmhouses and the living styles of the inhabitants have changed in mountain districts. Ochiai is situated in a remote mountainous area. The steep slopes of the mountainsides were cleared and farmhouses were built in a way that complements the unique landscape of the surrounding farmlands. We found quite a few farmhouses whose history could be traced back to the Edo period. Plans of those houses could be classified into two categories. It was found that, while the houses still maintained many traditional aspects or characteristics, most had been remodelled considerably by adding lavatories, baths and other modern facilities as well as constructing entrance and remodelling rooms. The authors also studied the temporal attributes and the effect of social demands as the reasons that the residents decided on additions and alterations of their farmhouses, most of remodelling took place between 1975 and 1985 when the occupants were reported to change their vocation.