Abstract: A coiled disk spring is prepared by closely winding a strip having a noncircular cross section into a coil shape with the face inclined at a predetermined angle with respect to the axis of the coil. The sectional shape of the strip may be appropriately selected in accordance with the intended use and, for example, when it is triangular or trapezoidal, a coiled disk spring having progressive nonlinear characteristics can be obtained. A coiled wave disk spring having progressive nonlinear characteristics can also be prepared by closely coiling the strip while bending the strip into a wavy form in the circumferential direction of the coiled spring.