To prevent emergency admissions and save medical costs, support should be provided to households that include people with complex care needs to allow them to continue living in their own homes. This community-based, cross-sectional study was conducted to (1) identify which departments that public health nurses (PHNs) worked have been the primary providers of support for households with complex care needs and (2) clarify the length of time required by each department to resolve primary health problems. We analyzed 148 households with complex care needs that were registered in City A from April 2018 to July 2019. Four types of departments were the primary support providers for complex care households: the department supporting persons with disabilities (n = 54, 36.5%), public/community health centers (n = 47, 31.8%), department of older adults (n = 29, 19.6%), and welfare offices (n = 18, 12.2%). The Mantel–Cox test showed that welfare offices mainly supported households in economic distress and needed significantly less time to resolve their primary health issues than other departments. For early detection and resolution of primary health problems for households with complex care needs, PHNs and healthcare professionals should focus on their economic distress and enhanced multidisciplinary approaches.