A lamp includes a lamp unit and an air-guiding ring. The lamp unit has a housing receiving a light-emitting element, as well as a fitted portion formed on an outer periphery of the housing. The air-guiding ring has an inner periphery forming a fitting hole and is fitted around the fitted portion of the lamp unit via the fitting hole. The air-guiding ring comprises a venting portion extending from an outer periphery to the inner periphery of the air-guiding ring.