PURPOSE: To make it possible to use two kind of antennas in common by preventing a radiation pattern from becoming disordered due to reflection on a metal surface provided between two kind of antennas by sticking a radio-wave absorber to the metal surface.

CONSTITUTION: Horns 3 are covered with a primary radiator frame 5 made of metal, radio-wave absorber 6 is stuck to the outside surface of this primary radiator frame 5, and dipole antennas 1 are arranged on the outside surface of a primary radiator frame 5 with radio-wave absorbers 6 interposed. As a result, radio waves radiated by antennas 1 are absorbed by radio-wave absorbers 6 to eliminate influences of radiation on the metal surface of a primary radiator frame 5 and consequently even when the antenna 1 composed of an array of horns 3 and antenna 1 are used in common, a radiation pattern by antennas 1 is prevented from becoming disordered.