This paper discusses effects of listening of the unpleasant sound to the changes of the correlation between psychological state evaluation using visual analog scale (VAS) and heart rate variability (HRV) analysis. The experiment employed 16 healthy subjects. The HRVs of the subjects are recorded when they listening of the unpleasant sound. And the HRVs are also recorded when they listening nothing. Furthermore, in order to investigate the psychological state evaluation, the subjects are required to answer the questionnaire on VAS, in both cases (when conducting the experiment and when not). The HRV data are analyzed by using FFT .The experiment result shows that there exists negative relationship between VAS data and coefficient of covariance in HRV.
