A wind power generation system, comprising: a rotor having a hub and at least two or more blades attached to the hub; a nacelle pivotally supporting the rotor via a rotation shaft connected to the hub; a tower supporting the nacelle; an airflow generation device provided in a leading edge of each of the blades, having a first electrode and a second electrode which are separated via a dielectric, and capable of generating plasma induced flow; a voltage application mechanism capable of applying a voltage between the first electrode and the second electrode of the airflow generation device; a measurement device detecting information related to at least one of output in the wind power generation system, torque in the rotor, and a rotation speed of the blades; and a control unit controlling the voltage application mechanism based on an output from the measurement device, characterized in that: when it is determined that an actual output in the wind power generation system, actual torque in the rotor, or an actual rotation speed of the blades is lower for a predetermined time than a set output in the wind power generation system, set torque in the rotor, or a set rotation speed of the blades set in advance at an axial wind velocity when the actual output, the actual torque, or the actual rotation speed is obtained, the control unit is arranged to control the voltage application mechanism to apply a voltage to the airflow generation device so as to generate plasma induced flow, and in that: when it is determined that a second actual output in the wind power generation system, second actual torque in the rotor, or a second actual rotation speed of the blades obtained while the plasma induced flow is generated reaches for a predetermined time a second set output in the wind power generation system, second set torque in the rotor, or a second set rotation speed of the blades set in advance at an axial wind velocity when the second actual output, the second actual torque, or the second actual rotation speed is obtained, the control unit is arranged to control the voltage application mechanism to stop application of the voltage to the airflow generation device. a rotor having a hub and at least two or more blades attached to the hub; a nacelle pivotally supporting the rotor via a rotation shaft connected to the hub; a tower supporting the nacelle; an airflow generation device provided in a leading edge of each of the blades, having a first electrode and a second electrode which are separated via a dielectric, and capable of generating plasma induced flow; a voltage application mechanism capable of applying a voltage between the first electrode and the second electrode of the airflow generation device; a measurement device detecting information related to at least one of output in the wind power generation system, torque in the rotor, and a rotation speed of the blades; and a control unit controlling the voltage application mechanism based on an output from the measurement device, characterized in that: when it is determined that an actual output in the wind power generation system, actual torque in the rotor, or an actual rotation speed of the blades is lower for a predetermined time than a set output in the wind power generation system, set torque in the rotor, or a set rotation speed of the blades set in advance at an axial wind velocity when the actual output, the actual torque, or the actual rotation speed is obtained, the control unit is arranged to control the voltage application mechanism to apply a voltage to the airflow generation device so as to generate plasma induced flow, and in that: when it is determined that a second actual output in the wind power generation system, second actual torque in the rotor, or a second actual rotation speed of the blades obtained while the plasma induced flow is generated reaches for a predetermined time a second set output in the wind power generation system, second set torque in the rotor, or a second set rotation speed of the blades set in advance at an axial wind velocity when the second actual output, the second actual torque, or the second actual rotation speed is obtained, the control unit is arranged to control the voltage application mechanism to stop application of the voltage to the airflow generation device.