An air vent for a vehicle, comprising: a duct housing having an air flow path formed therein and a circular air discharge hole provided at the front side thereof; a nozzle housing spherically coupled and provided to the inside of the duct housing so as to rotate freely in each direction; a damper having one pair of blocking plates, each of which has a semicircular shape with a connection gear and is rotatably assembled at the rear side of the nozzle housing so as to open or close the rear side of the nozzle housing; a nozzle fixedly coupled to the front side of the nozzle housing and having support members, which are formed inside so as to intersect with each other, a fixing member provided with a coupling hole in the center thereof, at which the support members intersect with each other, and a pin insertion hole formed at the rear side of the fixing member; a plurality of vanes positioned at the rear side of the support members of the nozzle, each having an upper fixing pin, which is assembled into the front surface of the nozzle housing, and a lower fixing pin, which is assembled into the pin insertion hole of the nozzle, so as to rotate, and having a guide pin positioned at the rear side of the lower fixing pin so as to be assembled passing the rear side of the fixing member of the nozzle; a fixing knob inserted into the coupling hole of the nozzle and having a guide groove, which is formed in a curved shape at the rear side thereof and fitted with the guide pin of the vane; a knob gear positioned at the rear side of the fixing knob and having an operation gear engaged with the connection gear of the damper; and a dial knob integrally assembled into the knob gear at the rear side thereof by penetrating the fixing knob from the front side of the fixing knob so as to operate the nozzle and the damper. a duct housing having an air flow path formed therein and a circular air discharge hole provided at the front side thereof; a nozzle housing spherically coupled and provided to the inside of the duct housing so as to rotate freely in each direction; a damper having one pair of blocking plates, each of which has a semicircular shape with a connection gear and is rotatably assembled at the rear side of the nozzle housing so as to open or close the rear side of the nozzle housing; a nozzle fixedly coupled to the front side of the nozzle housing and having support members, which are formed inside so as to intersect with each other, a fixing member provided with a coupling hole in the center thereof, at which the support members intersect with each other, and a pin insertion hole formed at the rear side of the fixing member; a plurality of vanes positioned at the rear side of the support members of the nozzle, each having an upper fixing pin, which is assembled into the front surface of the nozzle housing, and a lower fixing pin, which is assembled into the pin insertion hole of the nozzle, so as to rotate, and having a guide pin positioned at the rear side of the lower fixing pin so as to be assembled passing the rear side of the fixing member of the nozzle; a fixing knob inserted into the coupling hole of the nozzle and having a guide groove, which is formed in a curved shape at the rear side thereof and fitted with the guide pin of the vane; a knob gear positioned at the rear side of the fixing knob and having an operation gear engaged with the connection gear of the damper; and a dial knob integrally assembled into the knob gear at the rear side thereof by penetrating the fixing knob from the front side of the fixing knob so as to operate the nozzle and the damper.