A lamp unit includes: a projective optical system; a light deflector that is provided behind the projective optical system and selectively reflects incident light toward the projective optical system; a first irradiating optical system that irradiates a reflecting part of the light deflector with first light; and a second irradiating optical system that irradiates the reflecting part of the light deflector with second light. The first irradiating optical system and the second irradiating optical system are arranged such that a direction of irradiation by the first light and a direction of irradiation by the second light are not parallel when a front of the reflecting part is viewed.