This paper studies the problems of life sustaining treatment by the differences and contrasts of '생명' and '삶', the two korean equivalents of the English 'life'. And it considers and discusses how to revise the fundamental ideas and the value systems of Korean Constitution, if they are possible, according to the drastic changes of our thoughts and values in an era of rapid biotechnological change. And it closely analyses our ordinary thinking with regard to the concepts of sanctity and dignity. In addition, it investigates two ways of thinking in order to break the current standstill concerning the institutionalization of life-sustaining treatment after the Supreme Court's decision(2009.5.21.). Finally it suggests the new theoretical construction of life sustaining treatment.