Silicone rubbers are elastomeric materials and organic copolymers, of which backbone is siloxane with high bonding strength. Silicone rubbers have been used as an power insulator because they are well weather proof, ozone proof and have excellent electric characteristics, thermal stability, cold resistance and low surface energy. Especially, it is known that they have very excellent characteristics at 200[$^{circ}C$]. For this study, we made silicone rubbers as specimens and measured volume resistivity due to applied voltage and a variation of temperature 25[$^{circ}C$] to 180[$^{circ}C$]. Also we measured dielectric loss tangent due to applied voltage at temperature range 25[$^{circ}C$] to 180[$^{circ}C$] and frequency range 20[Hz] to 1${ imes}10^6$[Hz].