A sensor is disclosed. The sensor according to an embodiment of the present invention may include a substrate; a first electrode pattern disposed on one side of the substrate to form a layer; a second electrode pattern disposed on the one side of the substrate to form a layer and separated from the first electrode pattern; a sensing layer located on the one side of the substrate and covering the first electrode pattern and the second electrode pattern and containing a semiconductor; a protective layer located on the one side of the substrate and covering at least a part of the sensing layer, and containing a material different from that of the sensing layer; a first electrode pad disposed on the one side of the substrate to form a layer and electrically connected to the first electrode pattern; a second electrode pad disposed on the one side of the substrate and electrically connected to the second electrode pattern; and a housing accommodating the substrate and including a filter spaced apart from the substrate, wherein the substrate includes an opening formed adjacent to an outer boundary of the first and second electrode patterns.