The present invention relates to a power generation apparatus using water power, magnetism, and wind power, capable of obtaining sufficient torque, minimizing energy loss, and performing smooth power generation. The present invention includes: a plurality of runner blades which rotate in response to wind and tidal currents that apply forces in opposite directions; a horizontal rotating shaft in which the plurality of runner blades are connected thereto and a magnet is mounted thereto; a magnetism generation unit which generates a repulsive force with the magnet which is mounted onto the horizontal rotating shaft; a supporting unit which has the magnetism generation unit mounted thereto and supports the horizontal rotating shaft; a driven pulley which rotates in the same direction as the horizontal rotating shaft; and a turbine which is connected to the driven pulley by a belt.