 Heart rate variability HRV is known to reflect the balance of autonomic nervous system. Anxiousness, which tend to result from the deficient action of parasympathetic nervous system, likely to show low HRV. This study is to investigate the relationship between the surgery-related anxiety and the HRV which is known to reflect the balance of autonomic nervous system. Furthermore, this study also focuses on HRVs role as a predictor for aggressive emergence behavior, which might also be considered as partially related to imbalance of autonomic nervous system. 