This research uses the North Nara-machi district as a case study, and examines changes in family structure and dwelling styles, and the sustainability of residences in this historical environment from the perspective of the trend toward one-person households. A survey in 2000 of the North Nara-machi district showed that residents were aging and showing a tendency to live separately from their children. Based on this, a new survey was conducted focusing primarily on 33 one-person households. The results showed the subsequent changes of people living alone, as well as the characteristics of their residences, and the awareness of the residents. (1) Due to the passage of about 10 years since the 2000 survey, 19 of the 238 households covered by the survey showed a change in inhabitancy, or the residences became unoccupied or were converted into vacant lots or parking lots. Of those 19, 10 became one-person households. (2) When the characteristics of the residences of one-person households were examined, the underlying reasons for the difficulty of inheriting dwellings were major problems with dwelling size and the spatial composition of traditional townhouses. (3) In terms of inheritance of dwellings to the next generation, prospects for inheritance are strongly related to vacating or rebuilding the residence. Promoting a cycle where people move into homes in this district is an urgent issue.