To provide a thermally formable nonwoven fabric that can be formed in a prescribed shape by using, as short-cut fibers constituting the objective fabric fiber, undrawn thermoplastic short-cut fibers having latently stretching properties.

Undrawn thermoplastic short-cut fibers having latently stretching properties are preliminarily prepared. These short-cut fibers and, when desired, another kind of short-cut fibers such as rayon short-cut fibers are used to form fiber web through the carding process. A high-pressure columnar water flow is applied to the fiber web to tightly entangle these short-cut fibers mutually. Then, the entangled fibers are dried at about 100°C, in other words lower than the temperature at which the latently stretching properties of the undrawn thermoplastic short-cut fibers are not damaged thereby evaporating the water included in the nonwoven fabric. Thus, the objective nonwoven fabric for thermally forming is obtained. Instead of the high-pressure columnar water flow, the fiber web may be needle-punched to give the objective nonwoven fabric. This nonwoven fabric can be directly formed in a mold in no need of preheating. By the forming process, the undrawn thermoplastic short-cut fibers are well extended and formed into a prescribed shape.