The inventive concepts relate to a member for a gas sensor, a gas sensor using the same and a manufacturing method thereof, and more particularly, to a member for a gas sensor using a one-dimensional metal oxide nanofiber complex material containing hetero nanoparticle catalysts synthesized using apo-ferritins, a gas sensor using the same, and a manufacturing method thereof.According to embodiments of the inventive concepts, apo-ferritins containing hetero nanoparticle catalysts are mixed with an electrospinning solution, the mixture solution is electrospun to form complex nanofibers, and then a high-temperature thermal treatment process is performed to remove the apo-ferritins. Thus, the hetero nanoparticle catalysts are uniformly fastened to an inside and a surface of one-dimensional metal oxide nanofibers to form a member for a gas sensor. As a result, the member for a gas sensor has a high-sensitivity characteristic capable of sensing a very small amount of a gas and excellent selectivity capable of sensing various gases. In addition, a catalyst effect is maximized by the hetero nanoparticle catalysts uniformly distributed without aggregation. Furthermore, the member for a gas sensor and the gas sensor using the same can be mass-produced by a process method capable of effectively forming pores and of fastening high-performance catalysts.