Physical inactivity is a major contributor to non-communicable diseases and-after high blood pressure, tobacco use, and high blood glucose-is the fourth most important risk factor for mortality. The World Health Organization published “Global Recommendations of Physical Activity for Health” in 2010 in which it detailed the recommended levels of physical activity (PA) for the health of older and younger adults. Moreover, the official Japanese PA guidelines for health promotion (the “ActiveGuide”) suggest an additional 10 minutes of daily PA to increase healthy life expectancy across all generations. Despite growing evidence of the health benefits of PA and the existence of established recommendations for healthy aging, physical inactivity remains a major concern for older and younger adults. Recent public health studies have examined the social connections offered by relationships, as positive social relationships can affect health behaviors such as PA and outcomes such as mortality and are likely to promote healthy communities. We analyzed cross-sectional data from 8,592 (4,340 men and 4,252 women) non-disabled residents aged 65-84 years from all 18 districts of city A, Tokyo, to examine whether individuals’ PA levels are higher when individual- and/or community-level neighbor relationships (NRs) are active. Consequently, three main findings were revealed: First, individual-level NRs were consistently positively associated with PA in both sexes, and the dose-response relationships were significant. Second, in men, community-level NRs were positively associated with individual PA, regardless of the degree of individual-level NRs. Finally, significant cross-level interactions between individual- and community-level NRs were observed in the PA of men. An approach promoting NRs at both the individual and community level may be important, particularly to prevent physical inactivity among men.