The 4d transition metal oxide BaZrO3 is a perovskite compound which is widely utilized in the commercial industries. Its high proton conductivity enables its use as an electrolyte material for proton-conducting fuel cells. The low dielectric loss also offers advantages for widespread application in wireless communication technologies. Recently, high-quality BaZrO3 single crystal substrates have been developed, expanding its application as a platform for growing epitaxial thin films and developing new functional oxide films. In this presentation, we introduce our highquality BaZrO3 single crystal, grown by the optical floating zone method, and discuss the physical properties of BaZrO3 single crystal below room temperature.