We have constructed a gas sensor of SnO2 equipped with ceramic electrodes and a heater made of CaCu3Ru4O12, which demonstrated good device performance at high temperature. The CaCu3Ru4O12-based electrodes and heater were formed on Al2O3 substrates using a screen-printing process, which is cost-effective and suitable for mass-production. This all-ceramic device reached 600 °C at the lowest, and remained intact after one week of operation at 500 °C and rapid thermal cycling of 500 °C temperature changes within 10 s. We propose CaCu3Ru4O12 as a robust and reliable conducting material that can be a substitute for Pt in various devices.