An antenna module (1) according to the present disclosure has a dielectric substrate (20), an array antenna (10) including a plurality of patch antennas (111), an RFIC (40) electrically connected to the plurality of patch antennas (111), a signal conductor post (131) electrically connected to the RFIC (40), and a ground conductor post (132) set at a ground potential. The ground conductor post (132) is arranged, when viewed from a direction perpendicular to a first main surface of the dielectric substrate (20), between the signal conductor post (131) and a first side surface closest to the signal conductor post (131) of the dielectric substrate (20) in a polarizing direction of radio frequency signals to be emitted or received by the plurality of patch antennas (111).