Provided is a micro gas sensor including: a substrate; an open cavity and electrode pad separation grooves formed on the substrate; a plurality of electrode pads formed on an upper portion of the substrate and electrically insulated from each other by the electrode pad separation grooves; a micro heater connected to a plurality of the electrode pads by a bridge structure and suspended on the open cavity; a plurality of sensing electrodes formed on the same plane between the micro heater and a plurality of the electrode pads in a cantilever array and suspended on the open cavity; and a gas sensing film formed to be hung down between microelectrode finger spacings of a plurality of the sensing electrodes to represent changes in characteristics according to a gas concentration by contacting surfaces of the micro heater and a plurality of the sensing electrodes. Therefore, the micro gas sensor can have low power consumption, a rapid heating and cooling time, high durability, high sensitivity characteristics, and a capability of easily forming a gas sensing film by using various materials. In addition, the micro gas sensor can be miniaturized and mass-produced at low cost in a simple structure using only a single pattern mask.