PURPOSE: To make it possible to perform a power generation using a force caused by a flow of river, sewage or the like, by installing electromagnets and electrodes so as to face a movement region of a substance and generating power from the electromagnets using the movement as the force.

CONSTITUTION: A generator A is incorporated between drain pipes 2 and 3 in which sewage 1 flows. The generator A comprises a body 7 of a short pipe with the same diameter as the drain pipes 2 and 3, and flanges 8 and 8 formed on both ends of the body 7. In the generator A, elements are formed on the lowest part in which the sewage 1 always flows and both sides of the lowest part. Each element fixed perpendicular to the body 7 comprises electromagnets 10 formed so as to face the sewage 1 and a pair of electrodes 11 and 11 placed inside of the body 7 so as to interpose the tops of the electromagnets 10. Then, a coil is wound on the electromagnets 10, and the electromagnets 10 are fixed so that each electromagnet 10 is directed in the diametral center of the body 7. A power generation can be performed by carrying a current in the coil of the electromagnets 10 using a force F caused by an active flow of the sewage 1 according to the Fleming's right-hand law.