In the recent research, accumulation of stress has been shown to induce lifestyle diseases and mental/nervous diseases. In this research, visual search task was chosen to stress subjects, and the brain activity was measured by using near infrared spectroscopy (NIRS) and an electroencephalograph (EEG) was measured. Advantages of using these in combination are that it is relatively simple and less burdensome to the subject and it can be measured from the two viewpoints of neural activity and hemodynamics for the same brain region. As prior research, there are studies investigating the presence of stress by using brain activity, but there are no researches measuring the change in brain activity under continuous stress. The aim of this research is to extract features of active sites of brain function and electroencephalograms in stress accumulation. This research conducted experiments and analysis focusing on the two poles of Fp1 and Fp2 in international 10-20 method. In NIRS, when every time stress was accumulated, the difference was confirmed between right and left in brain activity. In EEG, there was no common feature between data in frequency and phase. From the above, it is possible to objectively and quantitatively evaluate the degree of stress accumulation by combining near-infrared spectroscopy and electroencephalograph by extracting a feature amount that changes every time stress accumulates in the EEG signal. As future tasks, the number of subjects should be increased. Also, different types of EEG analysis and the number of measurement points should be considered.