An array antenna device comprising: linear array antennas (10 to 80) in each of which a first element antenna (11a to 84a) and a second element antenna (11b to 84b) are alternately arranged linearly, the first and second element antennas (11a to 84a, 11b to 84b) having respective polarization planes perpendicular to each other, wherein the linear array antennas (10 to 80) are arranged in a direction perpendicular to an arrangement direction of the first and second element antennas (11b to 84b), in adjacent two of the linear array antennas (10 to 80), respective first element antennas (11a to 84a) and respective second element antennas (11b to 84b) are arranged so that positions of the respective first element antennas (11a to 84a) in the arrangement direction are shifted from each other by a half an arrangement interval and positions of the respective second element antennas (11b to 84b) in the arrangement direction are shifted from each other by a half the arrangement interval, the arrangement interval being an interval between the first element antenna (11a to 84a) and the second element antenna (11b to 84b), and in two of the linear array antennas (10 to 80), the first element antenna (11a to 84a) of one of the two and the second element antenna (11b to 84b) of another one of the two are arranged at a same position, and the second element antenna (11b to 84b) of the one of the two and the first element antenna (11a to 84a) of the other one of the two are arranged at a same position, the two being located two linear array antennas (10 to 80) away from each other characterized in that each of the first element antenna (11a to 84a) and the second element antenna (11b to 84b) includes a sub-array antenna in which multiple elements (11a-1, 11a-2, 11b-1, 11b-2) are linearly arranged in the arrangement direction of the first element antenna and the second element antenna in a corresponding one of the linear array antennas. linear array antennas (10 to 80) in each of which a first element antenna (11a to 84a) and a second element antenna (11b to 84b) are alternately arranged linearly, the first and second element antennas (11a to 84a, 11b to 84b) having respective polarization planes perpendicular to each other, wherein the linear array antennas (10 to 80) are arranged in a direction perpendicular to an arrangement direction of the first and second element antennas (11b to 84b), in adjacent two of the linear array antennas (10 to 80), respective first element antennas (11a to 84a) and respective second element antennas (11b to 84b) are arranged so that positions of the respective first element antennas (11a to 84a) in the arrangement direction are shifted from each other by a half an arrangement interval and positions of the respective second element antennas (11b to 84b) in the arrangement direction are shifted from each other by a half the arrangement interval, the arrangement interval being an interval between the first element antenna (11a to 84a) and the second element antenna (11b to 84b), and in two of the linear array antennas (10 to 80), the first element antenna (11a to 84a) of one of the two and the second element antenna (11b to 84b) of another one of the two are arranged at a same position, and the second element antenna (11b to 84b) of the one of the two and the first element antenna (11a to 84a) of the other one of the two are arranged at a same position, the two being located two linear array antennas (10 to 80) away from each other characterized in that each of the first element antenna (11a to 84a) and the second element antenna (11b to 84b) includes a sub-array antenna in which multiple elements (11a-1, 11a-2, 11b-1, 11b-2) are linearly arranged in the arrangement direction of the first element antenna and the second element antenna in a corresponding one of the linear array antennas.