A condenser microphone includes multiple condenser microphone units. Each unit includes an impedance converter. The condenser microphone units are connected in series such that outputs of the impedance converter in one of the condenser microphone units drive another of the condenser microphone units. A polarization voltage is accumulated to a DC voltage supplied from a DC voltage supply through a voltage adjuster to be applied to one of a diaphragm and a fixed electrode, and a voltage applied to the one of the diaphragm and the fixed electrode is adjusted by the voltage adjuster.