Vehicle headlight device

There is provided a headlight device (210L,210R) for a vehicle. The headlight device (210L,210R) includes: a lamp unit (10) that forms: a low beam light distribution pattern (Lo) including a cutoff line; and a plurality of types of additional light distribution patterns (LCL,RCL) each including an oblique cutoff line, wherein each of the oblique cutoff lines extends upwardly in a vehicle width direction toward the outside in an opposite lane region above the cutoff line, and wherein the shapes of the oblique cutoff lines are different from one another; and a controller (302) that controls the switching of the additional light distribution patterns in accordance with a situation of a forward vehicle in front of the vehicle.