An antenna apparatus is constituted by first, second, third, and fourth wire antenna elements and a connection element. The sum of the lengths of the first, second, and fourth wire antenna elements is ¼ the wavelength corresponding to a series-resonance frequency of the first, second, and fourth wire antenna elements. The sum of the lengths of the second, third, and fourth wire antenna elements is ½ the wavelength corresponding to a parallel-resonance frequency of the second, third, and fourth wire antenna elements. The sum of the lengths of the first and third wire antenna elements is ¼ the wavelength corresponding to a series-resonance frequency of the first and third wire antenna elements. The parallel-resonance frequency is higher than the series-resonance frequency of the first, second, and fourth wire antenna elements and lower than the series-resonance frequency of the first and third wire antenna elements.