A blade drive device includes: a blade; a board including an opening opened and closed by the blade; an actuator including a rotor; an output member driven by the rotor; a drive member rotatable relative to the board in response to the output member; a driven member driving the blade in response to the drive member; and a holder holding the actuator, wherein the holder includes an escape hole, the drive member includes: a support portion rotatably supported; a first connection portion connected with the output member; and a second connection portion connected with the driven member, and the first connection portion is positioned in the escape hole between the second connection portion and the support portion.