To make a high-beam light distribution pattern formed by a projector type lamp unit excellent in distant visibility, and to enhance distant visibility for a low-beam light distribution pattern as required as well, in a projector type lamp unit composed by arranging first and second light source units behind a projection lens.

This lamp unit of a vehicular headlight is structured such that an additional projection lens 42 for the second light source unit 16 is arranged around the projection lens 12, and a movable second shade 36 is provided for the second light source unit 16. By lighting the first light source unit 14, the low-beam light distribution pattern having a cutoff line is formed. A light distribution pattern having a cutoff line is additionally formed on the upper side of the above cutoff line by additional lighting of the second light source unit 16 to enhance its distant visibility. The high-beam light distribution pattern is formed by moving the second shade 36 to a shade release position.

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