In this experiment the comparison was studied between the muscular and the nervous fatigue and the flicker phenomenal value of the optic nerve. In order to measure the physical fatigue, various methods have been reported by many authers. In this experiment, a quantification of the fatigue was tried though the relation between the amount of mental activity and the FF (flicker frequency), which is useful in physical fatigue measurement with the change in respiration and pulse. In measuring the FF, respiration and pulse caused by physical work, it shows that the these three measured values are somewhat exponential, which might be called the exponential accumlation of fatigue. In mental activity slight relation was also found between fatigue and learning.