Objectives: The purpose of this study was to investigate the mediating effect of emotional expressiveness on the relationship between savoring beliefs and a subjective sense of well-being among middle-aged adults. Methods: A questionnaire survey was given to middle-aged adults aged between 40-65 years in Seoul, Gyeonggi, Daegu, and Gwangju during a two week period in March, 2018 (N=326). The measuring instruments used were the savoring belief scale, the emotional expressiveness scale, and the shortened subjective well-being scale. Correlations among the variables were examined and the structural equation model was verified by verifying the measurement model. Results: Three major results were found: First, higher savoring belief enhances emotional expressiveness and improves subjective well-being. Second, the higher the emotional expressiveness, the higher the subjective well-being. Third, emotional expressiveness had a partial mediating effect between savoring belief and subjective well-being. Conclusions: In order to increase the subjective well-being of middle-aged adults, the savoring belief of emotional expressiveness, which includes a cognitive psychological mechanism, should be highly antecedent.