PURPOSE: To provide a variable capacitance capacitor in which the capacitance can be set variably at a low bias voltage and the influence of disturbance such as a vibration, etc., is scarcely affected.

CONSTITUTION: A pair of variable electrodes 6a, 6b are superposed and arranged on an insulation support board 3, and electrode surfaces 10 of the electrodes 6a, 6b are opposed via a gap. The spring constants of the electrodes 6a, 6b are equally formed. When a vibration, etc., is applied to a variable capacitance capacitor, the capacitor is so formed that the electrodes 6a, 6b are similarly displaced. An external bias voltage is applied between the electrodes 6a and 6b, a distance between the electrodes 6a and 6b is displaced by the operation of an electrostatic force, thereby obtaining the electrostatic capacitor corresponding to the bias voltage.