Abstract: In a gas sensor for sensing reducing or oxidizing gases which comprises a semiconductive metal oxide film, there are provided stripe-like outer electrodes which define therebetween a continuous surface area and stripe-like inner electrodes which extend between, and parallel to, the outer electrodes so as to divide the continuous surface area into longitudinal segments which have different properties with respect to reducing or oxidizing gases such that different conductivity changes are generated for the different segments upon exposure to oxidizing or reducing gases.