To provide an electric power station being constructed at any place at a lower cost and facilitated in startup and shutdown.

A chain 5 in a declined state is spread between an upper chain sprocket 1 and a lower chain sprocket 3. A generator is connected to the upper chain sprocket or the lower chain sprocket. The chain is provided with many weight-supporting means 11. A weight-supplying means 17 is interposed above the upper chain sprocket. Weights 13 are supplied to the weight-supporting means from the weight-supplying means. The gravitational force of each weight supported by the weight-supporting means rotates the chain. Each weight- supporting means drops the weights around the lower end of the chain. The weight dropped from each weight-supporting means is returned to the weight- supplying means by means of a weight-lifting means 19.