Large-torque screwdriver

The invention discloses a large-torque screwdriver. The large-torque screwdriver is used for solving the problem that force application rods are prone to be lost. The large-torque screwdriver comprises a handle and a screwdriver bar used for screwing a screw, and further comprises a first pull rope, a second pull rope, a connecting frame, an extension spring, a first fixed pulley, a second fixed pulley, a first force application rod and a second force application rod; an inner cavity is formed in the handle; an opening is formed in the upper end of the inner cavity; the first fixed pulley andthe second fixed pulley are connected to the opening in the upper end of the inner cavity in a rotating mode; the lower end of the extension spring is connected to the lower end of the inner cavity; and the connecting frame is connected to the upper end of the extension spring. The large-torque screwdriver has the beneficial effect that the first force application rod and the second force application rod can be prevented