To provide an electric power generation method which is performed by a simple structure using a repulsive force of a magnet.

In an electric power generator, a displacer piston 40 of one pair of magnets connected with two same poles facing each other and a power piston 50 of another pair of magnets connected with two same poles facing each other are disposed in space where a magnet coil 2 is wound around a cylindrical frame 1, so that same poles of each of the magnets face each other. The power piston 50 is connected to a flywheel 60 while providing a phase angle so that the power piston gets close to the displacer piston 40 at its bottom dead point and follows the piston 40 on the way to its top dead point. Moreover, an annular magnet 5 is adhered to an outer peripheral surface part of the flywheel 60, and a fixed magnet 6 is disposed providing a predetermined distance in such a manner of gradually narrow in a rotational direction a gap with an outer peripheral edge part of the flywheel 60 so that the fixed magnet faces the same pole of the magnet 5, thereby causing the rotation of the flywheel 60 to generate electric power.