To provide a vehicular headlight capable of forming a light distribution pattern having a cut-off line at an upper end part by a projector type lamp unit equipped with a rotary shade, capable of switching between a left side and a right side light distributions at low beam, and capable of switching between the light distribution at low beam and high beam by simplifying rotation control of the shade.

The shade 32 is constructed by a rotation axis member arranged along a horizontal axial line Ax1 extending in a width direction of the vehicle, rotatable around a horizontal axial line Ax1, and a concave part 32B extending in a width direction of the vehicle is formed on a part of the perimeter of the outer surface 32A of the shade. In the above, two parts in the perimeter of the outer surface 32A are allocated to a first light distribution generating part 32A1 for generating a light distribution pattern of the low beam of the left side light distribution, and a second light distribution generating part 32A2 for generating a light distribution pattern of the low beam of the right side light distribution. The concave part 32B is constructed as a third light distribution generating part for generating a light distribution pattern for the high beam.