We simultaneously recorded palmar sweating and skin potential responses (SPRs) to determine their relationship. We used a highly sensitive capacitance hygrometer to simultaneously record sweating responses from the palm and SPR by DC. Ten healthy male college students were enrolled as subjects. Stimuli such as continuous short tone burst and hand claps were randomly provided to induce sweating responses and SPR. When a total of 202 SPR waves induced were investigated in relation to sweating responses, sweating responses were observed in all 140 responses in which positive components were included in the SPR waves. However, no sweating responses were observed in 62 responses in which the SPR waves exhibited monophasic negative waves. These results suggest a close relationship between the positive components in SPRs and surface sweating. Our findings have presented a clear answer to the controversy surrounding this problem, and have partially verified Edelberg's poral valve model.