To provide a natural power generation facility for always providing constant electric power, without being influenced by the weather or without being restricted by a construction place, without requiring supply of an energy source, operational manipulation and a maintenance-inspection.

A Foucault's pendulum is in repeating pendulum motion in the east-west directions by rotation of the earth when hanging the pendulum from a sufficiently high position, and uses this motional force for natural power generation. That is, a round bar-shaped or cylindrical permanent magnet is used as a weight of the pendulum, and a solenoid to which the magnet can go in and out is arranged on the right-left ends of the pendulum motion. AC electric power based on the Faraday's law is generated when the magnet goes in and out of the solenoid by the pendulum motion. However, since pendulum kinetic energy is gradually damped by power generation, an excitation cycle is incorporated into a power generation cycle, and power generation is substantially permanently continued.