This paper intends to identify regional characteristics of houses in Kasashima district in Kagawa prefecture is designed as the important preservation districts for group of traditional buildings. The results of the survey revealed that the interior of the house is characterized by the use of earthen floor with fittings, the use of zashiki and senzai to adjoin, and the use of earthen floors in the form of vertical holes for smoke ventilation. In particular, the earthen floor in the form of vertical holes is an old feature that needs to be carried on in the future.
