<p>Disclosed is a NOx sensor which gives an output of the same direction with respect to NO and NO2 with the same sensitivity, thereby precisely measuring total NOx concentration, and also which can be reacted with only NO2 according to a forming method of an oxide sensing electrode. The NOx sensor comprises an oxygen ion conductive solid electrolyte 10; one or more oxide sensing electrodes 20 formed at the oxygen ion conductive solid electrolyte 10; a first noble metal electrode 30 formed at the oxide sensing electrode 20; a second noble metal electrode 40 formed at the oxygen ion conductive solid electrolyte 10; and an electromotive force lead line 50 for the electrical connection of the oxide sensing electrode 20 and the second noble metal electrode 40. The oxide sensing electrode 20 and the second noble metal electrode 40 are connected in parallel to each other through the first metal electrode 30.</p>
