A collimator lens unit includes at least two lenses and substantially collimates a beam of light emitted from a solid-state light source unit of a Lambert emission type, wherein at least two faces of incidence faces and emission faces of the lenses constituting the two lenses are aspheric faces, one front aspheric face located close to the solid-state light source unit has a function of changing a luminous flux density distribution of the beam of light emitted from the solid-state light source unit to a predetermined luminous flux density distribution in which the luminous flux density in the vicinity of an optical axis of the collimator lens unit is higher than the luminous flux density in a peripheral portion separated from the optical, the rear aspheric face farthest from the solid-state light source unit has a function of substantially collimating the beam of light.