An antenna substrate includes a cap substrate including a first antenna conductor located on upper and lower surfaces of a first insulating layer; a frame substrate including an opening located in the second insulating layer and having an outer periphery that surrounds an individual of or a collective number of outer peripheries of the plurality of first antenna conductors in a top view; a base substrate including a second antenna conductor located on an upper surface of a third insulating layer; a first adhesive material adhering the first insulating layer and the second insulating layer; and a second adhesive material adhering the second insulating layer and the third insulating layer; and the first adhesive material and the second adhesive material include a first bonding member and a second bonding member having an adhesive strength to the second insulating layer greater than that of the first bonding member.