An apparatus and a method for operating a wind turbine capable of preventing the occurrence of damage of the blades by evading excessive irregular loads from acting on the blades in the slanting direction in the event of power failure when strong wind blows, are provided.The operating method of a wind turbine having a support 106 standing erect on the ground or on a ship; a wind turbine 100A with a nacelle 102 supported for swivel movement in a horizontal plane, a rotor 105 having a plurality of blades 101 and being rotated by wind force acting on the blades 101, and a generator being contained in the nacelle and connected to the rotor 105; a rotation driving mechanism 4 for swiveling the wind turbine 100A; and a brake device for controlling the rotation of the wind turbine comprises the step of: rotating the wind turbine to naturally follow the direction of wind in a state that the rotor is positioned in a downwind position when one of signals of abnormality in the generator or abnormality of undue load of wind to the blades is detected.