Humans continuously emit brain waves as long as they are alive and diversely reflect brain functions. Factors that cause changes in brain waves include personal differences, ages, changes in the state of consciousness, mental activities, and perception stimuli. In addition, normal or special waveforms may appear or the amplitudes and appearance ratio may increase due to these stimuli. Based on these characteristics, the present study was intended to see electroencephalogram (EEG) activities in response to diverse stimuli such as intellectual activities, visual stimuli, and auditory stimuli. Brain electric activities were recorded using an EEG-9200K. The international 10-20 system was used to attach scalp electrodes. The study subjects were 30 students that were at least high school graduates. The study subjects had no nervous system disease and all were right-handed. The results of the present study are as follows. First, during intellectual activities, the activity of the frontal lobe increased more than that of the temporal lobes and concentration improved further on problems consisting of drawings rather than letters. Second, when visual stimuli (anger) were given, Hz increased in the frontal lobe (Fp1, Fp2) but decreased in the temporal lobes. Third, when positive sound stimuli were given, slow waves appeared generally. On the other, when negative sound stimuli were given, sharp waves appeared. In addition, the activity of the temporal lobes increased in response to both positive and negative auditory stimuli. In conclusion, not only the activity of the frontal lobe but also EEG in the left brain increased in response to intellectual activities and larger responses appeared at negative stimuli compared to positive stimuli. In addition, whereas other studies reported that the right cerebrum was more sensitive to sounds compared to the left cerebrum, the present study showed higher sensitivity to sound in the left cerebrum. Therefore, the subjects in our experiment are thought to have been affected not only by auditory stimuli but also positive/negative emotions.