由於社會競爭力提升，國人普遍使用電腦處理工作上事務，長期使用終端機（Visual display terminal; VDT）所造成心智疲勞也隨之增加，不僅影響工作效率，更造成安全的威脅。許多心智疲勞相關研究以問卷方式進行，缺少科學客觀的數據。由於生理量測技術的進步，使用腦波（Electroencephalogram; EEG）等生理量測儀器來評估心智疲勞已很普遍，惟對心智疲勞歷程之相關研究仍極少見。本研究旨在探討心智疲勞之歷程，採用腦波量測技術進行客觀量測，並以NASA-TLX工作負荷評估量表進行主觀量測。分析項目包括：用以評估心智活動之腦波事件關聯電位（Event-Related Potential; ERP）及用以評估覺醒水準之腦波頻譜。本研究徵求自願之受測者，年齡介於18-25歲之間，實驗前量測其ERP與NASA-TLX工作負荷評估量表，實驗開始後進行8階段之著色方塊計數作業，每階段5分鐘，並記錄其腦波。著色方塊試驗是利用背景為黑色方塊為白色之33立方體，3面共27格，27格內隨機出現紅色正方形，讓受測者計數紅色正方形數量。實驗結束後再量測一次ERP與NASA-TLX工作負荷評估量表，實驗歷時70分鐘。研究結果顯示，著色方塊計數作業30分鐘後受測者呈現困倦程度有顯著增加，40分鐘以後又漸漸的恢復，實驗結束時疲勞度仍然比開始前增加。經歷70分鐘之作業後受測者之ERP量測結果顯示作業之後潛時在F4及Cz具有顯著減少，在振幅部分作業後是呈現較低狀況，代表著受測者訊息處理能力變差的。NASA-TLX工作負荷量表在身體負荷與精力耗費有顯著變化，意味著受測者經歷70分鐘之VDT作業後主觀感覺顯著之心智疲勞。 Owing to the rising of society competition, the personal computer has become widely used to treat the office affair. Since such work requires prolonged vigilance and mental activity, fatigue caused from visual display terminal (VDT) tasks frequently occurs in the workplace. That not only affects the work performance, but also hangs over the safety. There are many studies had been performed by using questionnaire, lack of scientifically objective data. For the progress of physiological measuring technique, the use of physiological measuring instruments, e.g. electroencephalogram (EEG) are more popular. While the study associated with fatigue has been found scarcely. The purpose of this study is to explore the process of mental fatigue. The EEG incorporated NASA-TLX rating scale are employed to evaluate the mental fatigue and examine its process. The voluntary subjects aged from 18 to 25 were participated in this study. The subject’s ERP and NASA-TLX rating scale were undertaken before experiment tasks. Eight sessions of colored-cube-calculating tasks were performed during experimental tests. It took 5 minutes for the subject to perform one session of task. The EEG was recorded during the experimental tasks. The colored-cube-calculating tasks were 3×3 cube in white color under black background presented from computer monitor. There are 3 faces presented on cube including 27 squares. Various amounts of red squares upon cube were appeared randomly. The subjects needed to calculate the amount of red square. The subject’s ERP and NASA-TLX rating scale were undertaken after experiment tasks again. The whole experimental tasks were performed in 70 minutes. The preliminary result revealed the subject’s drowsiness significantly increased during 30 minutes of colored-cube-calculating tasks and recovered gradually at 40 minutes later but did not come to the original level. The latencies and amplitudes of ERP measurement at F4 and Cz recording sites significantly decreased after colored-cube- calculating tasks. It demonstrates that the subject’s ability of information treatment deteriorated. For NASA-TLX rating scale, physical demand and effort had significant increase. It means the participant had subjective mental fatigue during 70 minutes of VDT tasks.