To provide a wind power generation device capable of reducing a site area required for its installation.

An aggregate of the wind power generation device is constituted in such a way that a first frame like circular ring capable of rotating centered on a transmission tower and a second frame like circular ring capable of rotating centered on the transmission tower below the first frame are attached to an intermediate part of the transmission tower installed on the ground through bearings, respectively, the first frame and the second frame are mutually fixed by a pair of vertical frames, and the wind power generation device is fixed to respective vertical frames so that they are symmetrically arranged relative to each other centered on the transmission tower.