A wind turbine generator provided with a sliding bearing as a yawing ring bearing that can reduce shifting of an axial center by making radial-direction clearances small. In a wind turbine generator in which a nacelle installed at the top of a tower is turnably supported via a yawing sliding bearing, the yawing sliding bearing is provided with a sliding member 33 disposed between top and bottom support surfaces of a flange formed mainly at a stationary portion and a turning portion; and a rolling element disposed between the stationary portion of the yawing sliding hearing and the turning portion.