A ground layer is disposed within a dielectric substrate. An antenna pattern that operates as an antenna is disposed so as to be closer to a first surface of the dielectric substrate than the ground layer is. A high-frequency device that supplies a high-frequency signal to the antenna pattern is mounted in or on a second surface of the dielectric substrate, which is opposite to the first surface. A plurality of signal conductor columns and a plurality of ground conductor columns that are made of a conductive material project from the second surface. Each of the signal conductor columns is connected to the high-frequency device by a wiring pattern, which is provided in or on the dielectric substrate, and the ground conductor columns are connected to the ground layer.