A microphone that identifies the direction along which acoustic waves propagate with one diaphragm, and has superior durability is provided. The microphone includes a circular diaphragm supported at a center portion thereof. When the diaphragm receives acoustic waves, each position around the center thereof will vibrate with a phase depending upon the direction of the acoustic waves. First electrodes are arranged on one surface of the diaphragm and second electrodes are arranged facing corresponding first electrodes to form a first capacitor. Third electrodes are arranged on the other surface of the diaphragm and fourth electrodes are arranged facing corresponding third electrodes to form a second capacitor. A controller applies a voltage to the second capacitors so that the capacitance of the first capacitors will be constant and identifies the direction along which the acoustic waves propagate based on the difference in the voltages applied to each of the second capacitors.