Disclosed is a gas sensor. A gas sensor according to one example of the present invention comprises: a first electrode and a second electrode which are formed on a base plate, which have an alternating power source applied to them, and which are positioned apart from each other; and a carbon nanotube powder or nanowire powder coated in regions formed between the first electrode and the second electrode, and the impedance of the nanotube powder changes depending on the concentration of a gas.
