To propose a specific procedure for replacing SF6 with air and to select appropriate parameters for internal arc tests, it is necessary to clarify the equivalent conditions causing the pressure rise due to air and SF6 arcing in the tests. In this paper, we describe the characteristics of the pressure rise due to air and SF6 arcing in a closed container and the ratio of the arc energy to the energy contributing to the internal pressure rise (kp) from an experimental viewpoint. Additionally, to verify the energy balance resulting from SF6 arcing in the container, the energy balance is discussed on the basis of the chemical reactions, radiation, and the melting and vaporization of the electrodes.