This study was conducted to determine the correlation between positive emtional contagion, depression, and up-regulating positive affect. It was also determined whether the mediating effect of up-regulating positive affect was significant in the relationship between positive emotional contagion and depression, and whether there is a difference in the mediating effect depending on savoring and enhanced positivity, the sub-factors of up-regulating positive affect. To this end, an online survey was conducted on 500 Korean adults, consisting of the Korean version of the Emotional Contagion Scale (K-ECS), Korean Response Styles to Positive Affect Scale (K-RSPAS), Center for Epidemiologic Studies Depression Scale-Revised (CESD-R). 493 data were used for the final analysis, excluding data from 7 people who responded insincerely. The results are, first, in the correlation analysis between variables, there was a significant correlation between all major variables except for the relationship between savoring and depression. Second, between positive emotional contagion and depression, the mediating effect of up-regulating positive affect and enhanced positivity was found to be significant, and the mediating effect of savoring was found to be insignificant. The results of this study are can be considered meaningful in that, unlike previous studies on emotional disorders, it explored depression by focusing on positive emotions. Also, by illustrating that positive emotional contagion is capable of decreasing depression through up-regulating positive affect and enhanced positivity, this study might be able to add a novel approach to dealing with depression.