The implementation of home-care robots is sometimes unsuccessful. This study aimed to explore factors explaining people’s willingness to use home-care robots, particularly among care recipients and caregivers. Surveys were conducted in Japan, Ireland, and Finland. The survey questionnaire comprised four categories (familiarity with robots, important points about home-care robots, functions expected from home-care robots, and ethically acceptable uses), with 48 items assessing users’ willingness to use home-care robots. The responses from 525 Japanese, 163 Irish, and 170 Finnish respondents were analyzed to identify common and distinct factors influencing their willingness to use these robots. Common factors across the countries included “willingness to participate in research and development,” “interest in robot-related news,” and “having a positive impression of robots”. The distinct factors for each country were: “convenience” in Japan; “notifying family members and support personnel when an unexpected change occurs in an older person” in Ireland; and “design” in Finland. Therefore, developers should determine potential users’ willingness to participate in the research and development of home-care robots and consider a system that involves them in the development process.