[영문]The study compares the effects of structural bases and functional elements of social support on mental health in Taiwan and the United States, using the study conducted in the United States by Lin, Ye, and Ensel (1999) as a reference. Based on a nationally representative sample of Taiwanese adults (n = 2,835), a fundamental similarity in social support structure and function between the two countries was observed. First, the structural bases of social support had a hierarchical order in their effects on depression: Binding (presence of an intimate relationship) was the strongest in reducing depression, whereas belonging (community participation) was the weakest, with bonding (social networks) in between. Regarding the functional elements, perceived social support was a better protector of mental health than actual social support, a finding in line with previous research. On the other hand, several notable differences in the structural bases and functional elements of social support between the two societies were observed, possibly due to the differential cultural and historical characteristics.