The present invention comprises: an LED; a light guide; a diffusion plate; and an air vent housing, wherein at least one shielding protrusion having a receiving portion is formed to protrude from the rear of the air vent housing having the irradiation hole formed therethrough into which the diffusion plate is inserted to be fixed, wherein a bent extension portion is formed to extend from one side of the light guide such that a locking protrusion inserted into the receiving portion formed in the shielding protrusion protrudes from the front thereof and an inflow portion, through which the light generated from the LED is introduced, protrudes from the rear thereof.