To investigate the effect of compound of high melting point materials into Cu on current chopping characteristics, the arc instability starting current and chopping current were evaluated for various Cu-base materials. As a result, both the arc instability starting current and chopping current of Cu base alloys were reduced by the addition of the refractory materials. In case of compounding high melting point metals, it was presumed that the reduction rate of chopping current was mainly related to the vapor generation ability of high melting point metals which were superheated by the energy of arc discharge. In case of compounding carbides or carbon, the reduction rate was affected by the chemical state of carbon in the material as well as the content of carbon.