An array antenna device comprising: a first dielectric substrate provided with a first conductor ground plane on a front surface or a back surface thereof; a plurality of patch antennas (3-1 to 3-9) provided in the first conductor ground plane , each of the patch antennas (3-1 to 3-9) having a circular shape; a plurality of conductive members , ends of which are connected to the first conductor ground plane to surround each of the patch antennas (3-1 to 3-9) individually and the conductive members surrounding a respective patch antenna (3-1 to 3-9) are equidistant from a center of said patch antenna (3-1 to 3-9); and a second conductor ground plane connected to each of other ends of the conductive members , wherein the first conductor ground plane is provided on one of, a) the front surface of the first dielectric substrate , a part of the plurality of conductive members penetrates the first dielectric substrate , and a remaining part of the plurality of conductive members functions as spacers for providing an air layer between the first dielectric substrate and the second conductor ground plane , and b) the back surface of the first dielectric substrate , the plurality of conductive members functions as spacers for providing an air layer between the first conductor ground plane and the second conductor ground plane , wherein the conductive member adjacent to at least two or more patch antennas among the plurality of patch antennas (3-1 to 3-9), out of the plurality of conductive members , is disposed at a position equidistant from a center of each of the at least two or more patch antennas adjacent to each other. a first dielectric substrate provided with a first conductor ground plane on a front surface or a back surface thereof; a plurality of patch antennas (3-1 to 3-9) provided in the first conductor ground plane , each of the patch antennas (3-1 to 3-9) having a circular shape; a plurality of conductive members , ends of which are connected to the first conductor ground plane to surround each of the patch antennas (3-1 to 3-9) individually and the conductive members surrounding a respective patch antenna (3-1 to 3-9) are equidistant from a center of said patch antenna (3-1 to 3-9); and a second conductor ground plane connected to each of other ends of the conductive members , wherein the first conductor ground plane is provided on one of, a) the front surface of the first dielectric substrate , a part of the plurality of conductive members penetrates the first dielectric substrate , and a remaining part of the plurality of conductive members functions as spacers for providing an air layer between the first dielectric substrate and the second conductor ground plane , and b) the back surface of the first dielectric substrate , the plurality of conductive members functions as spacers for providing an air layer between the first conductor ground plane and the second conductor ground plane , a) the front surface of the first dielectric substrate , a part of the plurality of conductive members penetrates the first dielectric substrate , and a remaining part of the plurality of conductive members functions as spacers for providing an air layer between the first dielectric substrate and the second conductor ground plane , and b) the back surface of the first dielectric substrate , the plurality of conductive members functions as spacers for providing an air layer between the first conductor ground plane and the second conductor ground plane , wherein the conductive member adjacent to at least two or more patch antennas among the plurality of patch antennas (3-1 to 3-9), out of the plurality of conductive members , is disposed at a position equidistant from a center of each of the at least two or more patch antennas adjacent to each other. <EOS>