A compound antenna apparatus includes a plurality of antenna units, a top case covering the antenna units, and a cable connected to one of the antenna units and led out of the top case, wherein the top case includes a case main surface, a case wall portion standing in the vicinity of an edge of the case main surface; and an opening formed by cutting an edge of the case wall portion so that the cable is pulled out to an exterior portion of the top case through the opening, and the opening having one surface and the other surface that face each other, a first rib and a second rib respectively formed and protruding at the surface and the other surface of the opening so as to sandwich the cable.