Abstract: The present invention provides a wind power generation device capable of reducing collision of a flying object against a blade or bird strike. The wind power generation device includes a tower set up on the ground, a nacelle fixed to the tower, a plurality of blades rotatably fixed to the nacelle via a hub, an obstacle search device capable of detecting a flying object existing in front, on the windward side, and a blade angle controller to control the change in angle of the blade including a rotation stop position. The obstacle search device searches for the flying object continuously, and when the flying object is determined to be approaching based on the continuous searching, the blade angle controller controls to change the blades to the rotation stop position.