Provided is a vehicular headlamp that includes a light source unit (6), a reflector (50), a heat sink (49), a fixation frame (9) fixed inside an external case (4) of a lamp, a movable frame (8) supported on the fixation frame (9) to be movable in a vertical direction, a lens unit (7) including a projection lens (14) and a lens holder (13) and supported on the movable frame to be movable in a horizontal direction, a first aiming operating shaft (10) that performs optical axis adjustment, and a second aiming operating shaft (11) that performs the optical axis adjustment. In particular, the lens unit (7) moves in the horizontal direction and the vertical direction with respect to the fixation frame (9) while a distance from a focus of light reflected by the reflector to the projection lens is constant, and the light source unit is fixed to the lamp housing (2) while the heat sink (49) is positioned outside the external case (4).