A wind turbine generator that can eliminate the penetration of rainwater and prevent the occurrence of failure is provided. The wind turbine generator includes: a plurality of wind-turbine rotor blades for receiving wind power; a rotor head to which the plurality of wind-turbine rotor blades are attached, the rotor head being rotated and driven by the wind power received by the plurality of wind-turbine rotor blades; a head capsule for covering the rotor head; a blade-side disc portion that extends from each wind-turbine rotor blade radially outward of the wind-turbine rotor blade and is inclined toward the head capsule; a cylindrical portion that is disposed substantially coaxial with each wind-turbine rotor blade and extends from the head capsule toward the tip of the wind-turbine rotor blade; a capsule-side disc portion extending radially outward from each cylindrical portion; and a bent portion that extends radially outward from the outer circumferential edge of each capsule-side disc portion and is inclined toward the tip of the wind-turbine rotor blade.