Up to now, the analysis of the event-related potential has been carried out by the averaging method or the frequency analysis method. However, the averaging method is defective in that high-frequency off-phased components tend to cancel each other out and so detailed information may easily be lost. On the other hand, in the frequency analysis, time-axis information may easily be lost. In addition, in the past analysis of data, the amount of fluctuation represented by the 1/f power spectrum has been treated in its entirety as noise. Novertheless, nonlinear phenomena as represented by chaos of fractals indicate the possibility of quantification in numerical analysis. In this paper, the fractal analysis of event-related potential is carried out, and its results are used to examine fluctuational conditions in intellectual activity. In addition, peaks equivalent to N100 or P300 did not show up clearly. This is considered to be because fractal analysis is more suited to the detection of variations in the inducement amount rather than that of peaks.