Wind power generation tower and construction method of wind power generation tower

A wind power generation tower for supporting a wind power generator in mid-air, comprising:

• a tower lower portion that includes at least three legs made of hollow concrete and erected on a foundation so as to tilt toward each other;
• a tower intermediate portion made of cone-shaped hollow concrete, arranged in a center of the at least three legs in a plan view, and including a lower end supported by the legs and an upper end thinner than the lower end;
• and
• a tower upper portion made of a steel pipe, protruding upward from the tower intermediate portion to support the wind power generator, and including a lower half portion supported by the upper end of the tower intermediate portion and an exposed body portion, wherein
• the tower intermediate portion has at least three flat surfaces formed at equal intervals in a circumferential direction on an outer circumferential surface of the lower end, and
• each leg has a flat joined surface facing the tower intermediate portion, and is fastened to the tower intermediate portion by a tensioner in a state where the joined surface is opposed to the corresponding flat surface.