A vertical axis wind turbine generator having a support stand (11), a shaft (41) defining the longitudinal direction and axis (19) of the generator. Two rotating members (12, 13) are coupled to the support stand (11) and the upper end of the shaft (41), thus being enabled to rotate about the axis (19). Two or more blades (14, 24, 34) having two free ends (15, 16) are connected by connecting members (17 and 18) to the two rotating members (12, 13), wherein movement of the first and/or second rotating members (12, 13) towards or away from one another causes the blades (14, 24, 34) to move further from, or closer to, the shaft (41).