An air purifying apparatus includes an air flow generating device for generating a flow of air, a nozzle spraying water to the air flowing through the air flow generating device, a plasma module performing a plasma reaction on the air containing the water sprayed from the nozzle, and oxidizing NOx in the air and converting it into NO3, an eliminator eliminating the NO3 converted in the plasma module and the water contained in the air and passing pure air through the eliminator and out of the air purifying apparatus and a water tank storing the water received from the eliminator, thereby heightening the removal efficiency of NOx from the air.