Background: The use of physical restraints by family caregivers with home-dwelling elders has not been extensively studied but it might be widespread. Furthermore, it is also not clear how home care providers who support family caregivers perceive the use of physical restraint in elders' homes. This study assessed family caregivers' and home care providers' knowledge and perceptions of physical restraint used with elders living at home in Japan, a country with the highest proportion of elders in the world and where family caregiving is common. Methods: We undertook a cross-sectional study of 494 family caregivers, 201 home helpers, 78 visiting nurses, 131 visiting physicians, and 158 care managers of home-dwelling frail elders needing some care and medical support in Japan, using questionnaires on knowledge of 11 physical restraint procedures prohibited in institutions and 10 harmful effects of physical restraints, perceptions of 17 reasons for requiring physical restraints, and experiences involving physical restraint use. Results: Family caregivers were aware of significantly fewer recognized prohibited physical restraint procedures and recognized harmful effects of physical restraint than home care providers, and differences among home care providers were significant. The average importance rating from 1 (least) to 5 (most) of the 17 reasons for requiring physical restraints was significantly higher among family caregivers than home care providers, and significantly different among the home care providers. Moreover, these differences depended in part on participation in physical restraint education classes. While 20.1% of family caregivers had wavered over using physical restraints, 40.5% of home care providers had seen physical restraints used in elders' homes and 16.7% had advised physical restraint use or used physical restraints themselves.