An apparatus for generating electric power from wind energy includes a blade device rotatable relative to a base to convert wind energy into a mechanical rotary power output, and having an upright rod connected with upright blades and coupled to a generator in the base to convert the mechanical rotary power output into electric power. Each blade has spaced wind-collecting ribs extending vertically from a first side surface thereof, thereby defining a wind-collecting space between any two adjacent wind-collecting ribs. A wind-collecting unit includes upright plates mounted on the base, angularly equidistant and disposed around the blade device. Any two adjacent plates define an inwardly converging wind-guiding channel therebetween. The plates are non-flat so that wind is guided by the plates to blow onto the first side surfaces of the blades via the wind-guiding channels.