PURPOSE: To attain a small size and light weight, to facilitate the processing and to improve the continuity reliability of throughholes by forming a dielectric board with a resin lamination board using glass fibers for a major material and selecting a specific thickness for the dielectric board.

CONSTITUTION: A dielectric board 1 is made of a resin lamination board made of glass fibers as a major material and the thickness of the dielectric board 1 is selected to be 0.1 to 1.0mm. Since the thickness of the dielectric board 1 is selected as thinner as 0.1 to 1.0mm, throughhole plating with sufficient thickness is formed by impregnating a plating liquid in a throughhole 2 even when its diameter is less than 1.0mm and the continuity reliability of the throughhole 2 is enhanced. Furthermore, when the diameter of the throughhole 2 is formed to be less than 1.0mm, a diameter of a terminal 3 connecting to the throughhole 2 such as a feeding terminal is made small and the weight of the entire antenna is made light further.