According to one embodiment, a lamp unit includes a light-emitting module, a lighting circuit, and a housing. The light-emitting module includes a light emitting portion having a semiconductor light-emitting element. The lighting circuit lights the semiconductor light-emitting element. The housing includes a case opening in the direction of irradiation of light, and a base on a side of the case opposite from the direction of radiation of the light. The lighting circuit is accommodated in the case, and the light-emitting module is mounted on the base at a position closer to the base with respect to the position of the lighting circuit.