A vehicular headlamp includes a light source on which a light emitting diode is mounted on a substrate, a heat spreading plate attached to the substrate so as to be capable of transferring heat, a holding member integrated with the heat spreading plate, a heat pipe comprising a first end portion and a second end portion, each of which having a circular cross-section, the first end portion being rotatably engaged with the holding member, and a heat sink connected to the second end portion.