The author has studied the effects of pain control by using the Anode-S-3 electro anesthesia in cavity preparations. The electric current value had used 4~10㎂. The results were as follows. 1) The 86 tests in cases of 110 tests as much as 78% of it have showed pain control effects and the 24 of tests as much as 22% had no effects in general. 2) The cases of perfect pain control was only made to 42 tests in cases of 110 tests as much as 38% of it. 3) The pain control with a little inordinary feeilng was 33 tests in 110 of it as much as 30% 4) The slight pain were recorded 22 cases as much as 21% of the tests. 5) The severe pain were recorded 12 cases as much as 11% of the tests. 6) Meanwhlie, the case of increasing pains by using electro-anesthesia was not recorded at all.