Abstract: Proposed is a gas sensing device. The gas sensing device includes a housing including an opening part through which a target gas to be sensed enters an inner space thereof, a sensor unit disposed in the inner space of the housing, and a connection passage connecting a first opening and a second opening that are formed in the housing such that the first opening and the second opening are open toward the inner space of the housing. According to the present disclosure, there is an effect that the gas sensing device capable of measuring a concentration of a gas with a high response speed and a high accuracy may be provided even if a pressure of a space inside the housing where the sensor unit is disposed increases.