Abstract: An antenna module includes an antenna substrate and a feed circuit. The antenna substrate has an upper surface and a lower surface, and a radiating element having a flat plate shape is arranged in the antenna substrate. The feed circuit 105 is mounted on the lower surface of the antenna substrate and supplies a radio frequency signal to the radiating element. The antenna substrate includes a dielectric substrate on which the radiating element is arranged, a ground electrode, a feed wiring, and carbides. The ground electrode is arranged between the radiating element and the lower surface in the dielectric substrate. The feed wiring transmits the radio frequency signal supplied from the feed circuit to the radiating element. The carbides are disposed on at least a part of a side surface connecting the upper surface and the lower surface in the dielectric substrate.