An antenna element includes: a radio transceiver that transmits and receives a radio wave; a signal input pad; a ground layer; an antenna that has a connection portion for electrically connecting the radio transceiver to the ground layer and the signal input pad; a silicon substrate on which the antenna is formed; and an insulating film for electrically insulating the silicon substrate from the antenna. The radio transceiver is disposed on a first surface of the silicon substrate with the insulating film interposed therebetween. The ground layer and the signal input pad are disposed on a second surface of the silicon substrate opposite to the first surface thereof with the insulating film interposed therebetween. The connection portion is disposed to penetrate the silicon substrate.