不管在工作上、家庭中使用電腦已相當普遍，作業場所使用電腦作業稱之為終端機 (Visual Display Terminal, VDT) 作業，因為此類工作需以座姿長時間專注於心智活動，在工作場所時常發生VDT作業引起之心智疲勞。本研究採用心率變異度(Heart Rate Variability，HRV)評估人員於電腦終端機作業對心智疲勞之影響。本研究選定的對象為使用電腦文書作業的上班族共20位（包括男性：9位、女性：11位）。受測者藉由VDT作業前、作業1.5小時後與聆聽音樂15分鐘後，三個實驗階段，比較受測者自覺疲勞評量表對心理疲勞的主觀感覺，與心率變異度客觀量測在三個實驗階段之變化情形。各實驗階段以成對t檢定比較自覺疲勞評量表指數的差異，結果顯示VDT作業前、後，達顯著性的上升（p<0.01）；VDT作業後與聆聽音樂後，達顯著性的下降（p<0.01）但未能回復至VDT作業前之水準。以成對t檢定比較心率變異度（HRV）之低頻/高頻(LF/HF)差異，結果顯示VDT作業前、後，達顯著性的上升（p<0.05）；VDT作業後與聆聽音樂後，達顯著性的下降（p<0.05）且接近VDT作業前之水準。研究結果整體而言，以自覺疲勞評量表與HRV之LF/HF都顯示，VDT作業後的心智疲勞度較作業前有明顯的疲勞。VDT作業後，藉由聆聽音樂後的心智疲勞度較作業後有明顯的放鬆，表示聆聽音樂有降低交感神經活性的效果。聆聽音樂後與VDT作業前相較，經自覺疲勞評量表的主觀評估顯示，聆聽音樂後無法恢復到VDT作業前的水準；HRV的LF/HF客觀量測顯示，聆聽音樂後之生理疲勞指標與VDT作業前的狀態相近，故表示聆聽音樂後有助於心智疲勞放鬆，但在主觀量測卻顯示受測者心理層面感覺精神狀態仍無法回復作業前之水準，但在客觀之HRV生理指標則顯示受測者之疲勞指數已回復至接近作業前之水準。 The use of computers in our life is omnipresent, either in the workplace or at home. The work using computer is called Visual Display Terminal (VDT) work. Since such work requires prolonged vigilance and mental activity with sedentary work, fatigue caused from VDT tasks frequently occurs in the workplace. The aim of the study is to assess mental fatigue induced during a VDT task using Heart Rate Variability (HRV). Twenty VDT workers participated as volunteer subjects in this study (including 9 males and 11 females). Three sessions including before VDT tasks, after tasks for 1.5 hours and listen to music for 15 minutes, were undertaken in the experiment procedure. The subjective fatigue measure from fatigue rating scale and objective measure from HRV for mental fatigue were analyzed and compared by statistical techniques. The results shows the fatigue rating scale after VDT was increaesed significantly (p<0.01), after VDT tasks and listening to music was decreased (p<0.01) but not to restore to the state before VDT tasks. The Low Frequency/High Frequency (LF/HF) of HRV after VDT tasks was increased significantly (p<0.05). After VDT tasks and listening to music, LF/HF was decreased significantly and close to before VDT tasks. According to the research depended on subjective fatigue measure and LF/HF of HRV, the mental fatigue were increased after VDT tasks. After VDT tasks and listening to music the mental fatigue had obvious relaxation compared to after VDT tasks. It indicated that listening to music is contributive to reduce the active of Sympathetic Nervous System (SNS). Comparison with before VDT tasks, the subjective sensation after listening to music was unable to restore before VDT tasks. The physiological index of LF/HF after listening to music demonstrated that the value is close to that before VDT tasks. The study showed that listening to music is helpful for dispelling mental fatigue. We also found that the mental condition in psychological of subjects unable to restore to before VDT tasks by subjective measure, but the physiological index by objective measure of HRV showed the fatigue index may restore to the state before VDT tasks.