Disclosed is an antenna apparatus, including: a multi-layer substrate having at least two substrates in a stacking manner and having a first through hole; an amplifying circuit on one face of the multi-layer substrate; a ground pattern formed between two adjacent substrates of the multi-layer substrate; an antenna pattern formed on the other face of the multi-layer substrate; and a first comb electrode having comb teeth and a second comb electrode having comb teeth, both of which are formed around the antenna pattern on the other face of the multi-layer substrate. The first comb electrode is electrically connected to the antenna pattern. The second comb electrode is electrically connected to the ground pattern through the first through hole. The comb teeth of the first comb electrode and the comb teeth of the second comb electrode are spaced from one another at predetermined intervals in a staggered manner.