To provide a method for producing a belt, in which the belt excellent in wearing feeling and appearance is produced as a long belt based on human engineering and the long belt is cut into an adequate length when used and the cut belt can be attached to the waist of skirt, underwear, etc., being convenient for storage.

High frequency vibration is applied to the surface of a linear belt-like woven fabric or knitted fabric while applying mechanical load to the woven fabric or the knitted fabric so as to spread either one edge of the linear belt-like woven fabric or knitted fabric. The high-frequency vibration may be applied to a woven fabric or a knitted fabric previously formed in a curved belt-like shape or may be applied to the surface of curved belt-like woven fabric or knitted fabric while applying mechanical load so as to spread the edge on the protruded side of the woven fabric or knitted fabric previously formed in the curved belt-like shape. The high-frequency vibration can be applied by using ultrasonic wave. Granular or dot print-like adhesive may be applied to one surface of the woven or knitted fabric before applying high-frequency vibration to the woven fabric or the knitted fabric. The belt can be attached to the waist of underwear by only applying heat with an iron, etc., by the adhesive.