A lamp apparatus for a vehicle which radiates only a p-polarized beam without radiating an s-polarized beam which is reflected by water collecting on a road surface by filtering light which is radiated to a road surface which is wet by rain, preventing reflection of light by water, whereby it is possible to prevent light from blinding the people in oncoming vehicles, so safety from oncoming vehicles is secured and since light having a uniform waveform is radiated, lighting feeling is improved.