近年來快樂的研究一直受到重視。然而臺灣的成年人快樂嗎？雖然聯合國（United Nations）（2019）統計指出，臺灣國民的快樂排在全球第25名，比起亞洲國家表現還要好，但這排名以國家為分析單位，不是針對個別樣本探究。本研究透過問卷調查法，自編快樂量表蒐集571位成年人資料經過分析獲得以下結論：一、臺灣國民的整體快樂良好，其中在人際關係、身心健康、幸福感受、生活滿意度都高於平均值，尤其在人際關係與幸福感的快樂面向最好。二、在控制個人背景變項之後，國民參與休閒以及纾解壓力，在國民的樂觀性與快樂程度之間具有部分中介效果。然而參與休閒和纾解壓力對於快樂的中介效果沒有明顯差異，代表這兩個中介變項相同重要。針對結論深人討論，提出具體建議。本研究貢獻在於運用嚴謹統計方法，分析臺灣國民的快樂發現，樂觀性與快樂之間存在著參與休閒與及纾解壓力之中介因素。這代表要提升國人快樂，參與休閒及纾解壓力的必要性。

In recent years, the study of happiness has been paid attention to, but were adults in Taiwan happy? Although the United Nations (2019) statistics indicated that Taiwan’s happiness ranked 25th in the world, which was better than Asian countries’ performance, but her ranking was the country-based analysis, and was not an exploration of individual samples. This study used a questionnaire survey method and compiled a self-compiled happiness scale to collect data on 571 adults. After statistical analysis, the following conclusions were obtained: 1. The overall happiness of Taiwanese people was good, which included interpersonal relationships, physical and mental health, happiness, life satisfaction was higher than average, especially in terms of interpersonal relationship and happiness. 2. After controlling personal background variables, citizens’ participation in leisure and stress relief had a partial mediating effect between the citizens’ optimism and happiness. However, there was no significant difference between participating in leisure and relieving stress in the mediating effect of happiness, which meant that these two mediating variables were of the same importance. This research had an in-depth discussion on the conclusions and made specific suggestions. The contribution of this research lied in the use of rigorous statistical methods to analyze the happiness factors of Taiwanese people and found that there were mediated factors (leisure participation and stress relief) between the people’s optimism and happiness. This provided people with the need to increase happiness, participated in leisure and relieved stress.