Provided is a gas flow sensor that includes a heat-sensitive element for measurement disposed inside a duct through which a gas to be measured flows and a support mechanism for supporting the heat-sensitive element for measurement inside the duct. The heat-sensitive element for measurement includes an insulating film; a thin film thermistor portion formed on the surface of the insulating film with a thermistor material; a pair of comb electrodes which have a plurality of comb portions and are pattern-formed on the thin film thermistor portion using a metal so as to face each other; and a pair of pattern electrodes which are pattern-formed on the surface of the insulating film and are connected to the pair of comb electrodes. The support mechanism is disposed such that the planar direction of the insulating film is parallel to the direction of gas flow in the duct.