Abstract: According to the invention, in order to obtain hinges which, even if small-sized, can create a great rotational torque and, moreover, permit ready alignment of details with the rotational moment of an opening/closing body, such as a lavatory seat or lid or accentuation of any part of the action thereof, there is provided a pair of composite torque hinges each consisting of; a rotating cylinder disposed to be rotatable around a fixed shaft; a cam mechanism which is provided within the rotating cylinder and on which a compression spring is caused to work so as to control the rotational torque of the rotating cylinder; and a torsion spring which is also provided within said rotating cylinder and functions in a direction to cancel the rotational torque of the rotating cylinder in a specific rotational direction.