To provide a rear lamp unit for a vehicle which is provided with a desired cut pattern on an outer lens so that the light-emitting area can be increased. A rear lamp unit is provided with upper and lower outer lenses for guiding light emitted from light-emitting diodes to the outside the vehicle. The upper and lower inner lenses are provided between the light-emitting diodes and the upper and lower outer lenses, respectively, and the upper and lower inner lenses are disposed at locations apart from the upper and lower outer lenses, respectively.