A wind power generator is provided in which a reduction in weight is achieved by reducing the wall thickness of a nacelle, and an increase in the amount of heat input to the interior of the nacelle from sunlight is suppressed. In a wind power generator in which driving/power-generating mechanisms linked to a rotor head to which wind-turbine blades are attached are accommodated and installed inside a nacelle, a coating of high-reflectivity paint is formed on at least part of the outer wall that receives sunlight.