Matters related to human life and death and medical healing are the concerns of patients, physicians, and other related persons, including family members of the patients. Existing medical decision-making models include paternalism and informed consent. However, these models have the limitation of being one-sided or unidirectional. Accordingly, shared decision-making is now emerging as a superior model of medical decision-making. In this model, physicians, who have medical knowledge, patients, and family members, who may have the best understanding of the patients’ life, jointly participate in making medical decisions. As a medical decision-making model, shared decision-making is often regarded as a process based on mutual respect and partnership between physicians and patients. A goal of medicine is to remove pain brought about by disease. In making medical decisions for individual patients, not only physicians, but also the patients themselves and their family members can play an important role. Family members can play such a role because of their familiarity with the patient and knowledge of his or her values. This is especially true in times of medical crisis when individual patients may have difficulties in making reasonable decisions. Thus, shared decision-making is an ideal method of decision-making, one in which patients, physicians, and family members work together to choose the best course of medical treatment for the patient.