Plasma processing is widely used in the mass production of industrial devices. A RF sputtering can be used for insulator and dielectric materials. When capacitive coupled plasma (CCP) is used for RF sputtering, the state of discharge has to be researched. The relationship between the ratio of areas of the electrodes and the ratio of DC bias voltages in magnetron sputtering was investigated, because it determines the acceleration voltage for ions, and may play an important role in sputtering. The imperfection of plasma control leads to problems in mass production. The relationship between the ratio of areas of the electrodes and the ratio of DC bias voltages in magnetron sputtering was investigated in this study. Moreover, the simulation results of some models that are different in chamber size or gas pressure were obtained. These results were compared with the experimental results and the difference was discussed. The results of simulations regarding the relationship between a bias voltage of a target (V _dc) and gas pressure with the same chamber, and between V _dc and chamber size correspond to the experimental results qualitatively. However, the changes are much less than in the experiments, especially with respect to chamber size. Considering distributions of neutral gases and radicals, the accuracy for V _dc may be improved.