A microphone includes: a needle-like electrode; an opposite electrode facing the needle-like electrode; a discharge section formed between the needle-like electrode and the opposite electrode; a high-frequency oscillating circuit including the discharge section and producing a high-frequency discharge at the discharge section; a sound wave introduction section through which a sound wave is introduced to the discharge section; and a modulated signal extracting unit that extracts a signal modulated, according to the sound wave oscillated by the high-frequency oscillating circuit and introduced to the discharge section. The high-frequency discharge is produced at the discharge section as the high-frequency oscillating circuit performs high-frequency oscillation with the discharge section between the needle-like electrode and the opposite electrode as a return path, and a frequency modulation is performed as an equivalent impedance of the discharge section changes according to the sound wave.