Elastic properties are fundamental knowledge for structural designing. Under the development of proton-conducting ceramics fuel cells (PCFCs), there is no doubt about the importance of elastic properties. However, the systematic study about component materials of PCFCs has been insufficient, and obtained elastic properties cannot cover the entire operation conditions. Low sinterability and processability of solid electrolytes prevent from adopting conventional measuring method for high temperature metals. We therefore modified an ultrasonic transmission method for pellet type specimens and measured elastic properties in 10, 15, 20 mol% yttrium doped barium zirconate from room temperature to 700ºC. The results indicated that elastic moduli such as Young's modulus and shear modulus gradually decrease with temperature rising to approximately 200°C and the slope became moderate over 400°C. Elastic moduli in BZY decreased by 30-40% from room temperature to 500°C. Observed temperature dependences are important basic properties for the structural designing of PCFCs.