Through 5 case studies, the constructional characteristics of partitions and ceilings with wood back-up structures in apartments' interior were compared. As results, the following facts have been found: the partition's back-up structure plays a central role in influencing the constructional efficiency of whole interior finish work, the construction method of ceiling's back-up structure is the one which needs improvement urgently, the relation between the Element Density and Man-Minute value of one element in ceiling's back-up structure is inverse proportional, and corresponding movement between partition and ceiling's back-up structures appears in the Man・Minute/m^2.
