Provided is a vehicular headlamp including a lamp casing configured by a lamp housing having an opening at least at one side thereof and a cover that covers the opening of the lamp housing, and a lamp unit disposed within the lamp casing. The lamp unit includes: a light source unit having a light source; a movable shade configured to be rotatable and change the shielding quantity of light; a solenoid having an output shaft which moves in a left-and-right direction and configured to rotate the movable shade; a rotation shaft configured to function as a rotation fulcrum of the movable shade, the axial direction of the shaft corresponding to the left and right direction; and an orthogonal transformation mechanism configured to convert a movement action of the output shaft to a rotation movement of the movable shade.