A lamp unit for forming a light distribution pattern having a given cutoff line in an upper end portion thereof includes a light source, a transparent member which receives light from the light source from rearward and projects the light distribution pattern forward, and a light shade which is provided between the light source and the transparent member and which shades a part of the light emitted by the light source. The transparent member is configured to reflect, by a front surface of the transparent member, the light that enters the transparent member from rearward thereof, then to reflect again the light to forward thereof by a rear surface of the transparent member, and then to radiate the light from the front surface. The light shade is configured to shade the light going from the light source directly toward the rear surface.