A hemispherical Luneberg dielectric lens includes a hemispherical center layer having a hemispherical outer surface, and a plurality of hemispherical dome-shaped layers each having concentric hemispherical inner and outer surfaces, the outer surfaces of the center layer and dome-shaped layers having different diameters and the inner surfaces of said dome-shaped layers having different diameters. The center layer and dome-shaped layers are successively concentrically fitted into one another and integrated into a hemispherical shape. The center layer is a foam molding of ceramic-containing thermoplastic resin expanded beads, while each of said dome-shaped layers is a foam molding of thermoplastic resin expanded beads containing 0 to 80 % by weight of a ceramic. The ceramic content per unit volume of the center and dome-shaped layers decreases from the center layer to the outermost dome-shaped layer, and the standard deviation of the apparent density of each of the center and dome-shapedlayers is 0.07 g/cm3 or lower.