To mount a blade member to be supported at both ends thereof and to configure the blade member with light and simple members, thereby efficiently utilizing a wind force.

A wind turbine device for a wind power generator includes: a pair of endless chain members 1 arranged to circulate within a predetermined range in a vertical direction; a pair of chain wheel members 2 on which the chain members are put; many blade members 3 with their both ends connected to the pair of endless chain members 1 at a constant interval; a frame body 4 rotatably supporting all the chain wheel members 2 via rotary shafts 6, 7; the rotary shaft 6 of the upper chain wheel members 2 connected to a generator 5 via two transmission chain wheels 5a, 6a and a transmission chain member 5b, the rotary shaft 7 of the lower chain wheel members 2; a support member 8 rotatably supporting the frame body 4 in a horizontal direction; a direction control mechanism arranged between the support member 8 and the frame body 4; and a guide rail mechanism 9 guiding the blade members 3 to circlulate while being oriented in a predetermined direction.