A vehicular lamp includes: a main light source that emits light for forming a predetermined irradiation pattern; an optical member that allows the light emitted from the main light source to travel toward a front side in an irradiation direction to form the irradiation pattern; a heat dissipation member that releases heat from the main light source to outside; and a light guide member that guides light from an auxiliary light source provided as a separate body from the main light source. In the heat dissipation member, the heat dissipation member is provided with an opening part that opens a mounting surface provided with the main light source, and the light guide member guides light from the auxiliary light source toward the mounting surface through the opening part.