An antenna module (1) comprises: a substrate (100) including a first flat plate part (100a) and a second flat plate part (100b) that are contiguous with one another, the directions normal to the respective flat plate parts intersecting with one another; first patch antennas (10a to 10d) formed on the first flat plate part (100a); and second patch antennas (20a to 20d) formed on the second flat plate part (100b). At least one row of said first patch antennas (10a to 10d) is arranged in a row direction along a boundary line (B) between the first flat plate part (100a) and the second flat plate part (100b). At least one row of said second patch antennas (20a to 20d) is arranged in said row direction. The dimension, in a second direction, of each of the second patch antennas (20a to 20d) arranged in a row farthest from the boundary line (B) is smaller than the dimension, in a first direction, of each of the first patch antennas (10a to 10d), said second direction being perpendicular to said row direction and parallel to a principal surface of the second flat plate part (100b), said first direction being perpendicular to said row direction and parallel to a principal surface of the first flat plate part (100a).