A wind turbine generator includes a plurality of blades that radially protrude from a rotor head about an axis of a main shaft, and a pitch axis rotation mechanism that is provided in the rotor head to rotate the blade about a pitch axis P. The pitch axis rotation mechanism includes an actuator that is supported by the rotor head, and has a stretchable rod which is supported by the rotor head, and a link structure that links the rod to the blade. The actuator extends on the axis of the main shaft.