Gas detecting device

A gas detecting device detecting characteristics of a gas under test, the gas detecting device comprising:

• a shell component, the shell component including a gas passage and a groove, the gas under test passing through a detecting area on a path of the gas passage along the gas passage;
• a sensing component, the sensing component being disposed inside the shell component, the sensing component including a substrate, a sensor disposed on the substrate, and a laser light source electrically connected to the substrate, wherein the sensor and the laser light source are respectively disposed corresponding to the detecting area;
• and
• a dust blocking element, the dust blocking element being detachably disposed in the groove of the shell component, the dust blocking element including a base and a cover disposed on the base, wherein the cover is light permeable, the cover is disposed corresponding to the detecting area, and a vertical projection of the cover on the substrate and a vertical projection of the sensor on the substrate at least partially overlap with each other.