To provide a two-frequency antenna which do not necessitate to increase a packaging area and packaging volume as compared with a single frequency antenna and allows to be easily produced.

First and second dielectric substrates 5, 6 are formed on both the sides of a ground conductor plate 3 and 1st and 2nd antenna elements 1, 2 having respectively different dimensions are respectively formed on the sides opposite to the ground conductor plate sides, of the plates 5, 6. A metallic conductor 4 for short-circuiting the 1st and 2nd antenna elements 1, 2 and the plate 3 and feeders 7, 8 for respectively supplying power to the elements 1, 2 are also formed. The two-frequency antenna can be formed by the constitution.