An air vent for a vehicle, comprising: a duct housing having an air path provided inside, a vane member assembled in a front portion of the air path so as to adjust air discharge direction, a damper rotationally coupled to a rear portion of the air path so as to open or close the air path; a dial knob rotationally coupled to a side surface of the duct housing and having a knob coupling hole formed in a rear portion; characterized in that: said duct housing comprises a cover fixing boss formed in an outside surface, the air vent further comprises a damper rotation member coupled to a damper rotation shaft on the side surface of the duct housing and having a pinion gear formed on the outer circumferential surface thereof; a knob connector having coupling members protrudingly formed at both end portions such that the coupling member at one end portion is fitted into the knob coupling hole; a damper connector, of which one side end is link-connected to the other end of the knob connector and the other side end is provided with a rack gear at an upper portion thereof so as to be engaged with the pinion gear, and having a guide hole formed inside in the back-and-forth longitudinal direction so as to be placed by the cover fixing boss of the duct housing; and a guide cover having an insertion part, into which the cover fixing boss is fitted and of which outer diameter surface comes into contact with the guide hole of the damper connector, and a finishing part provided to be stepped on the outside thereof so as to be coupled to the cover fixing boss by a coupling member. a duct housing having an air path provided inside, a vane member assembled in a front portion of the air path so as to adjust air discharge direction, a damper rotationally coupled to a rear portion of the air path so as to open or close the air path; a dial knob rotationally coupled to a side surface of the duct housing and having a knob coupling hole formed in a rear portion; characterized in that: said duct housing comprises a cover fixing boss formed in an outside surface, the air vent further comprises a damper rotation member coupled to a damper rotation shaft on the side surface of the duct housing and having a pinion gear formed on the outer circumferential surface thereof; a knob connector having coupling members protrudingly formed at both end portions such that the coupling member at one end portion is fitted into the knob coupling hole; a damper connector, of which one side end is link-connected to the other end of the knob connector and the other side end is provided with a rack gear at an upper portion thereof so as to be engaged with the pinion gear, and having a guide hole formed inside in the back-and-forth longitudinal direction so as to be placed by the cover fixing boss of the duct housing; and a guide cover having an insertion part, into which the cover fixing boss is fitted and of which outer diameter surface comes into contact with the guide hole of the damper connector, and a finishing part provided to be stepped on the outside thereof so as to be coupled to the cover fixing boss by a coupling member. said duct housing comprises a cover fixing boss formed in an outside surface, the air vent further comprises a damper rotation member coupled to a damper rotation shaft on the side surface of the duct housing and having a pinion gear formed on the outer circumferential surface thereof; a knob connector having coupling members protrudingly formed at both end portions such that the coupling member at one end portion is fitted into the knob coupling hole; a damper connector, of which one side end is link-connected to the other end of the knob connector and the other side end is provided with a rack gear at an upper portion thereof so as to be engaged with the pinion gear, and having a guide hole formed inside in the back-and-forth longitudinal direction so as to be placed by the cover fixing boss of the duct housing; and a guide cover having an insertion part, into which the cover fixing boss is fitted and of which outer diameter surface comes into contact with the guide hole of the damper connector, and a finishing part provided to be stepped on the outside thereof so as to be coupled to the cover fixing boss by a coupling member.