To provide a variable capacitance capacitor having largely variable capacitance.

Leg sections 2a and 2b are formed on a substrate 1 at an interval, and a support beam 3 is put on the sections 2a and 2b across the space between the sections 2a and 2b. Cantilevers 4 and 5 are respectively extended to the right and left from the beam 3 at intervals from the surface of the substrate 1, and movable electrodes 6 and 7 are respectively formed on the surfaces of the cantilevers 4 and 5 facing the substrate 1. In addition, a drive electrode 11 oppositely faced to the electrode 7, a drive electrode 10, and detecting electrode 12 oppositely faced to the electrode 6 are formed on the substrate 1, with the electrode 12 formed on the front end side of the cantilever 4. When a Coulomb force is generated between the electrode 7 and 11, the cantilever 5 moves toward the substrate 1, and the cantilever 4 is raised. When a Coulomb force is generated between the electrodes 6 and 10, the cantilever 4 moves toward the substrate 1. When the cantilever 4 moves in the vertical direction, the capacitance between the electrodes 6 and 12 changes.