Novel　tungsten　oxide　sensors　were　fabricated　based　on　Hall　Effect　and　their　NO(2)　gas　sensing　properties　were　examined.　Tungsten　trioxide　was　grown　by　vapor　evaporation　of　metal　tungsten　filament　in　an　oxygen　atmosphere.　A　WO(3)　thick　film　was　deposited　on　the　four　Au　electrode　to　be　a　WO(3)　sensor.　The　sensor　was　tested　between　magnetic　field　in　a　plastic　test　chamber.　The　gas　sensing　experiment　revealed　that　at　the　NO(2)　concentration　of　40　ppm,　a　sensitivity　of　3.27,　a　response　time　of　36　s,　and　a　recovery　time　of　45　s　were　observed　at　room-temperature.　The　effect　of　WO(3)　based　on　Hall　Effect　on　the　sensing　characteristic　is　discussed.