Place attachment refers to 'the bonding that occurs between individuals and their meaningful environments', and its association with community participation and well-being has been clearly demonstrated. It has two aspects: social (e.g. social capital) and physical (e.g. nature and convenience). A previous study shows that the social aspect contributes more robustly to place attachment than does the physical aspect. Furthermore, although previous studies suggest that factors contributing to place attachment differ between urban and rural areas, this has not yet been empirically demonstrated. This study, therefore, examined whether these factors vary with population density, conducting a secondary analysis of large-scale survey data in Japan. It analysed 1,394 Japanese adults (764 men; 630 women), who answered all items and responded correctly to the satisficing items. Average participant age was 43.47 years (range 18-75, SD = 10.62). Participants were divided into four groups considering the population density of their municipality of residence. Structural equation modelling was used to conduct a simultaneous multigroup analysis for each group (CFI =.97, RMSEA =.02). Moreover, an ANOVA was conducted with four groups based on population density as the independent variable. The results indicated that areas with higher population density exhibited stronger place attachment and greater convenience but had less nature and social capital. Based on the ANOVA results, the findings from the multigroup analysis suggest that social capital substantially contributes to place attachment, regardless of whether an area is rich in it. However, nature contributes to place attachment in high-density areas where nature is not rich, whereas convenience contributes to place attachment in low-density areas where convenience is lacking. Therefore, enhancing the natural environment in urban areas and improving convenience in rural areas may increase people's place attachment, promote their well-being, trust in society, and active community participation.