The purpose of this study was to examine the amount of $eta-endorphin$ and pain threshold according to time sequences in applying experimented TENS and MENS(pre treatment, posttreatment, 25 minutes after the treatment). This test was to aim at showing the effects of the experimental $eta-endorphin$ and pain threshold applied to the randomly selected twenty healthy men in their twenties. The subjects were divided into two group(ten for TENS and the other ten MENS). The results obtained are as follows : 1. There was no significant difference in the $eta-endorphin$ between TENS and HENS(p>0.05). There was no difference in the pain threshold at pretreatment and posttreatment(p>0.05), but there was some difference at 25 minutes after the treatment(p<0.05). 2. The group of TENS in the experimental $eta-endorphin$ had the highest level of $14.40{pm}3.098$ at posttreatment, but the level decreased a little according to time passed. And in the experimental pain threshold, the level went to the highest plateau of $2.92{pm}0.483$ at 25 minutes after the treatment. 3. The group of MENS in the experimental $eta-endorphin$ had the highest plateau of $14.20{pm}3.967$ at posttreatment, but the level decreased a bit according to time passed also. And in the experimental pain threshold, the level went to the highest plateau of $2.49{pm}0.617$ posttreatment. 4. There were some differences of the experimental $eta-endorphin$ in TENS group at pretreatment and posttreatment(p<0.05). There were some differences in the experimental pain threshold between pretreatment and posttreatment as well as between pretreatment and 25 minutes after the treatment(p<0.05) MENS did not influence the experimental $eta-endorphin$ and pain threshold. This experiment showed that TENS increased the levels of the experimental $eta-endorphin$ at posttreatment and increased the levels of the experimental pain threshold untill 25 minutes after the treatment. Therefore, the time of sustaining pain in TENS group was longer than that of MENS group. Also, MENS showed that it increased each level of the experimental $eta-endorphin$ and pain threshold, but these levels were not statistically meaningful.