This paper explains about secular change of residents and dwelling unit floor plans in Pilot House Housing Development built in 1947, which was one of the oldest "Free Planned Condominium " in Japan. Main results are as follows. 1) Early nuclear family residents with 2 children became old couples or old couples with an adult child. 2) Vacated spaces left by separations of children were often used passively. 3) Dwelling unit floor plans which are older than 10 years were changed more than 80 %. 4) Extension of living rooms increases recently.
