According to one embodiment, an antenna module includes a substrate, a first antenna, an array antenna, and a radio frequency (RF) module. The first antenna includes a first radiation element arranged on the substrate and a first ground plane arranged on the substrate. The array antenna includes a plurality of second radiation elements arranged on the substrate. The substrate includes a first surface and a second surface. The first ground plane is arranged on at least the first surface of the substrate. The plurality of second radiation elements are arranged on the second surface of the substrate and opposed to the first ground plane via the substrate.