A gas detecting module is disclosed. A gas-inlet concave and a gas-outlet concave are formed on a sidewall of a base. A gas-inlet-groove region and a gas-outlet-groove region are formed on a surface of the base. The gas-inlet concave is in fluid communication with a gas-inlet groove of the gas-inlet-groove region, and the gas-outlet concave is in fluid communication a gas-outlet groove of the gas-outlet-groove region. The gas-inlet-groove region and the gas-outlet-groove region are covered by a thin film to achieve the effectiveness of laterally inhaling and discharging out gas relative to the gas detecting module.