Highly sensitive La doped with ITO-SnO2:La thin film sensors for CO2 gas were fabricated. For the sensors, we used the well-known spray pyrolysis method technological route with SnO2, LaCl2, C2H5OH, H2O as the host and dopant materials. The sensors had a maximum sensitivity for spraying at 550℃. Compared to other sensors, our sensors improved sensitivity, response, recovery time, reaction rate and stability. A good linearity of sensitivity as a function of gas concentration exhibited the possibility of concentration meter use.