Abstract: A rotary power generating apparatus has the first, second piston magnet members, the crankshaft, the first, second guide members and the first, second fixed magnet members and the first, second demagnetizing belts. The first, second piston magnet members and the first, second fixed magnet members are arranged so that the top pole surfaces and fixed pole surfaces having equal polarity, oppose each other. The first, second demagnetizing belts have demagnetizing magnet parts, having magnetic forces weaker than that of the magnetic poles of the top pole surfaces and different from the polarity of the top pole surfaces, and non-magnetic force parts.

Abstract: Obtaining of a secure reciprocation of piston magnets and enhance the continuity to obtain a continuous rotary power. The rotary power generating apparatus has the first, second piston magnet members, the crankshaft, the first, second guide members, and the first, second fixed magnet members and the first, second demagnetizing rotary drums respectively having the first, second demagnetizing cylindrical bodies. The first, second piston magnet members and the first, second fixed magnet members are arranged so that the top pole surfaces and fixed pole surfaces, having equal polarity, oppose each other. The first, second demagnetizing cylindrical bodies have demagnetizing magnet parts, having magnetic forces weaker than that of the magnetic poles of the top pole surfaces and different from the polarity of the top pole surfaces, and non-magnetic force parts.