We have been developed a new idea to reduce the flow-induced noise generated from HVAC system equipped in a vehicle cabin that makes a loud noise. Porous materials whose acoustic transmission loss was relatively lower was attached to the surface of fins set at the nozzle exit of the air-flow. Experimental results showed that the flow-induced noise generated broad-banded was reduced about 3 -5 dB by attaching porous materials. Further, in our wind tunnel experiments, using these porous materials did not result in increasing of the air-flow resistance. Therefore, we can conclude that there is a possibility that our technique will become a countermeasure to reduce the flow-induced noise generated from the HVAC system.