This chapter explores how people signed a Living Will conceptualize their understanding of a meaningful life, under which circumstances death becomes more desirable than life and how these notions are connected to the concepts of happiness and well-being. It analyzes the perceptions using Mathews and Izquierdo's four dimensions of well-being: physical, interpersonal, existential and institutional. The chapter provides a brief overview of changes that have been made to medical practices and decision-making processes applied in end-of-life situations and discussions of Living Wills in Japan. It considers how signing a Living Will is related to the critical awareness of life-sustaining treatments, considering the physical, interpersonal and existential dimensions of well-being. The chapter shows Living Will, a strategy available to people in Japanese society allows them to maintain agency in end-of-life situations, to avoid situations associated with the irreversible loss of well-being and happiness and prevent themselves from becoming a burden to relatives and negatively affecting the latter's well-being and happiness.