The purposes of this study are to map residential areas of elderly people at high risk of undernutrition (food desert areas), and to assess mobile sales wagons as a form of support for disadvantaged shoppers. The research methods are as follows: (1) prepare a map that shows high-density areas of elderly people who suffer from poor nutrition; (2) compare the locations of undernourished elderly people in relation to stations where mobile sales wagons stop; and, (3) assess the efficiency of mobile sales wagon support by comparing these locations, and suggest improvements. The findings of this research are as follows. (1) There are long distances between the locations of poor food access areas and high-density areas of undernourished elderly people. Local communities of people with limited access to shopping facilities are mainly located in suburban agricultural areas, whereas residential areas of undernourished elderly people are located in suburban agricultural areas and city centers. (2) Wagon stations are mainly located in residential areas of relatively poor food access areas; there are no stations in city centers. (3) The customer ratio of sales wagons tends to be higher in areas where many low-functioning independent elderly people live, and in areas where many economically poor seniors and those isolated from family members dwell.