To clarify the knowledge and beliefs of the Japanese general population related to legal options, pain medications, communication with physicians, and hydration/nutrition in end-of-life care, and to explore the associations between end-of-life care they had experienced and these beliefs, a questionnaire survey was conducted on two target populations: 5000 general population subjects and 866 bereaved family members of cancer patents who died in 12 palliative care units in Japan. The respondents were requested to report the legal knowledge about end-of-life options, pain-related beliefs, communication-related beliefs, and hydration/nutrition-related beliefs, and their experiences with end-of-life care. A total of 3061 responses were analyzed (effective response rate, 54%). The respondents were classified into six groups: no bereavement experience (n = 949), those who had lost family members within the past 10 years from noncancer diseases at institutions (n = 673), those who lost family members from noncancer disease at home (n = 264), those who lost family members from cancer at institutions other than palliative care units (n = 525), those who lost family members from cancer at home (n = 86), and those who lost family members from cancer at palliative care units (n = 548). Across groups, 32-45% and 50-63% of the respondents stated that treatment withdrawal and double effect act were legal, respectively. Between 34% and 44% believed that cancer pain is not sufficiently relieved, 27-38% believed that opioids shorten life, and 24-33% believed that opioids cause addiction. Communication-related beliefs potentially resulting in barriers to satisfactory end-of-life discussion were identified in 31-40% ("physicians are generally poor at communicating bad news") and in 14-25% ("physicians are not comfortable discussing death"). The bereaved family members of the patients who died in palliative care units were significantly more likely than the other groups to believe that cancer pain is sufficiently relieved, and significantly less likely to believe that opioids shorten life, that opioids cause addiction, that physicians are generally poor at communicating bad news, and that physicians are uncomfortable discussing death. Between 33% and 50% of the respondents, including families from palliative care units, believed "artificial hydration should be continued as the minimum standard until death," while 15-31% agreed that "artificial hydration relieves patient symptoms." A significant proportion of the Japanese general population has beliefs about legal options, pain medications, and communication with physicians that potentially result in barriers to quality end-of-life care. As their experiences in specialized palliative care significantly influenced their belief, systematic efforts to spread quality palliative care activity are of value to lessen these barriers and achieve quality end-of-life care.