Thermoelectric materials can directly convert thermal energy into electrical energy. Research and development of thermoelectric generators have been actively carried out to use waste heat. Electrodes are necessary to take out the electrical power from the thermoelectric couples. However, large portion of the generated electrical power is often lost at the interface between electrode and thermoelectric materials. Though oxide materials are promising for a thermoelectric generator at a high temperature, they are not practically used as the joining technique is not established. Not only low contact resistance but also sufficient mechanical strength is required for the joining. In this report, tin alloy solder was attempted for cold side junction to obtain low contact resistance and high mechanical strength at the interface. Wettability of the solder to Ca3Co2O6 and the thermoelectric generating properties were improved by adding titanium to tin alloy.