A device for chaological evaluation of human factor comprises a Lyapunov index calculator 23 for calculating a Lyapunov index by analyzing a digitized sound signal, which is changed into a digital data from a sound uttered by a person, by using a chaological method a Lyapunov index change detector 24 for detecting a change in the Lyapunov index of the uttered sound, which is calculated by using the Lyapunov index calculator 23. A psychosomatic activity is predicted and determined by measuring a level of the load generated in the cerebrum on the basis of the change in the Lyapunov index detected by the Lyapunov index change detector 24.
