In order to clarify the instability phenomena of a low current in the vacuum, the optical characteristics of a low current vacuum arc was investigated by using Cu, CuW, CuCr, CuBi, and AgWC electrodes. We measured the spectrum-line intensity distribution against wavelength during arc discharge for each electrode. It was found that for Cu, CuW, CuCr, CuBi and AgWC electrodes, the total amount of the spectrum intensity from 350nm to 950nm wavelength (SI) increases in the order of Cu, CuCr, CuBi, AgWC, and except for CuW the chopping current decrease in the same order. For each component of every electrode material, the spectrum intensity and its attenuation speed of the neutral vapor at current chopping (Ucn, dUcn/dt) were investigated.It was found that the attenuation speed at current chopping decreases in the order of Cu, CuW, CuCr, CuBi and AgWC, the chopping current decreases in the same order.We will inspect the current chopping phenomena by observing the intensity change of the neutral vapor, and discuss relationship of electrode material and the chopping current from a new viewpoint of evaporation ability and the plasma decay speed.