Abstract: Provided is an impeller including a first portion including a first hub and a plurality of primary blades each extending while being spaced an equal distance from each other along an outer circumference of the first hub and a second portion including a second hub coupled to a lower side of the first hub by using a projection-groove coupling manner and a plurality of secondary blades each extending while being spaced apart from each other along an outer circumference of the second hub. Here, when a projection angle between a leading edge (L.E.) and a trailing edge (T.E.) of each of the primary blades is ?1, and a projection angle between a leading edge (L.E.) and a trailing edge (T.E.

Abstract: Provided is a dual rotor wind turbine having two rotor assemblies. In the dual rotor wind turbine, an inlet guide vane is placed at a lower location in front of each rotor assembly and a rotor shaft of the rotor assemblies is placed in back of a vertical shaft, so that the rotor shaft is offset from the vertical shaft. Thus, the gravity center of the wind turbine is located in a lower portion of the wind turbine, so that a stable balance of the wind turbine can be realized and the vertical shaft can be smoothly rotated relative to a fixed shaft.