This study is intended to analyze the preference of one-room apartment according to the type of life style of single people between 20 and 30 years age. The major findings were as follows: 1) The single people prefer the one-roon apartment(90.2%). 2) The Life styles were classified into 5 types: tradition preservation. self-fulfillment, fashion-pursuit. economy priority. convenience-pursuit. 3) The preference of a one room apartment is strongly influenced by all types of life styles regardless of tradition preservation.