To convert gravitational energy, which makes a weighed object fall from a higher place to a lower place, into motive energy, by putting the weighed object in a vessel, mounting the weighed object on a pallet, and hanging the pallet.

A weighed body is hung. The weighed body is required to weigh a certain amount so as to utilize gravitational energy. The weighed body weighing a required amount is put in a vessel, which is then mounted on a pallet. A chain is placed onto a geared pulley disposed in a derrick. The weighed body is hung from the chain. When the weighed body starts to go down owing to the gravity, gravitational energy is generated in the course of nature. When the geared pulley starts to rotate, a shaft of a generator also rotates, which converts the gravitational energy into electric energy.