A variable capacitance device that operates properly at a point along a signal line through which a high-voltage RF signal passes while reducing a necessary DC voltage includes a substrate, a beam, and lower drive electrodes. The beam is connected to the substrate through a support portion. Lower drive electrodes and the beam generate a capacitance when a DC voltage is applied, and an electrostatic force due to this capacitance deforms the beam. The lower drive electrodes face the beam and are coupled to each other through the beam. An RF signal propagates between the lower drive electrodes.