A wind-driven generator capable of efficiently generating electricity by effectively using energy of weak wind independent of the direction of the wind, having a simple structure, and capable of beingeasily increased in size and output. The wind-driven generator has a wind tunnel constructed from a tubular member vertically upstanding from a foundation, a large number of wind collection plates extending in the normal direction from the peripheral wall of the tubular member, a top plate for closing gaps between the wind collection plates and also closing the upper opening of the tubular member, wind intake openings provided on the peripheral wall of the tubular member and leading the wind collected by the wind collection plates into the wind tunnel, reverse flow prevention means provided at the wind intake openings and allowing only the flow of wind from the outside to the inside of the tubular member, a turbine driven by wind ejected from one end of the wind tunnel, and a generator driven by the turbine.