A vehicle lamp assembly includes a case, and a bulb cassette for mounting the a light bulb in the case. The case is formed of a resin material having a low thermal resistance and defines an interior space. The case includes at least one partition wall defining a planar partition wall surface to partition the interior space respectively into one and another chambers. The bulb cassette is received in an opening of the case for accommodating a light bulb within the one chamber thereof and includes at least one planar heat shield wall formed of a heat resistant resin which extends in adjacent contact along the planar partition wall surface so as to shield the at least one partition wall and the other chamber from heat generated by the light bulb in the one chamber.