工作時數過長，容易讓人處在憂鬱的危機中，尤其工作超過四十小時越多，則憂鬱危機愈高。本研究以全國高中職、國中、及國小教師為對象，希望瞭解是否在教師族群中，工作時數不同，其憂鬱程度也不同，以及個體的主觀幸福感是否能在工作時數與憂鬱程度之間，扮演中介變項的角色。本研究以分層隨機抽樣方式抽取樣本，共獲得984位教師的有效樣本，分別以主觀幸福感量表及台灣憂鬱症量表對該批樣本進行測量。研究結果發現：1.教師的工作時數越長，其憂鬱程度有愈高的趨勢；2.不同職別的教師間，工作時數有顯著的不同；3.主觀幸福感可在高中職教師的工作時數與憂鬱程度間扮演中介變項的角色。文末並對為實務工作及未來研究提出建議。 Past research indicated that long working hours may increase the risk of depression, especially when working for more than 40 hours. This study explores the relationship between the number of work hours and depression among high school, junior high school, and elementary school teachers. The mediating role of subjective well-being was also examined. Nine hundred and eighty four teachers were randomly selected from the north, central, and south regions of Taiwan. All participants completed two questionnaires – the Subjective Well-Being Scale and Taiwan Depression Scale – for assessment of subjective well-being and depression. Results show that teachers with longer working hours have higher risk of depression. Second, there were significant differences in the number of work hours among the three groups of teachers. Third, subjective well-being mediated work hours and depression among high school teachers. Finally, suggestions for practice and future research are proposed.