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.