Abstract: Provided is a dismantling method of a tower-type wind power generation system in which scaffolding is not required around a tower body. After climbing on a work bench set outside an outer wall of a tower body and removing a lower end part of an upward-tapering part in an upper end part of the tower body over the entire periphery of the tower body, the tower body is sequentially removed from an uppermost part of a cylindrical part of the tower body below the upward-tapering part to gradually dismantle the tower body from the top. The remaining upward-tapering part of the tower body from which the lower end part is dismantled first is supported by a jack provided in an inner column while being lowered, along with the dismantling, into an internal cavity of the cylindrical part of the tower body below the upward-tapering part and is placed on a placement protrusion provided on an inner wall of the tower body.