Provided are a composite metal oxide material, a method of manufacturing the same, and a gas sensor using the same as a sensing material thereof. The composite metal oxide material may include polycrystalline nanofibers and at least one of microparticles and nanoparticles. The use of the composite metal oxide material makes it possible to improve structural, mechanical, thermal, and lifetime stabilities of the gas sensor. Further, the presence of the microparticles and/or nanoparticles allows the gas sensor to have a base resistance lower than that of a nanofiber-based gas sensor. Since the microparticles and/or nanoparticles are attached to the nanofibers, the composite metal oxide material can have an increased mobility of electrons or holes and an increased surface area, and thus, the gas sensor can have fast response/recovery speeds and high gas sensitivity.