Objectives : This study was designed to investigate the effect of PC6 and SP4 on autonomic nerve system in healthy adults. Methods : 22 healthy adults were recruited and randomized into the study group or control group. The study group (real acupuncture group) was acupuncturcd on PC6 and SP4. The control group (sham acupuncture group) was acupunctured superficially near PC6 and SP4 but not the exact points. The subjects rested for 10 minutes, and were then acupunctured. After 15 minutes, acupuncture needles were removed and the subjects rested for another 15 minutes. Heart rate variability(HRV) was continuously measured during the study period by FM-150 (digital Holter ECG recorder). Results : In the real acupuncture group. LF(low frequency) significantly decreased during the acupuncture period(p<0.05). LF/HF ratio also had a significant decrease during acupuncture period and the decrease was maintained during the post-treatment period as compared with the pre-treatment period. In the sham acupuncture group. LF significantly increased during the acupuncture period but LF/HF ratio had no significant changes. Conclusions : The results suggest that acupuncture on PC6 and SP4 can increase parasympathetic activity and balance autonomic nervous system.