A color-developing composite short fiber having a length of 0.01 to 100 mm is obtained by cutting a color-developing short fiber capable of reflecting visible rays and interfering with visible rays consisting of two or more kinds or polymer compounds having different refractive indices which are laminated alternately. A color-developing structure is formed by binding particles of the short fiber to one another, dispersing the short fiber in a mixture with other materials or adhering the short fiber on the surface of a support. Further, a color-developing composite short fiber having a length of 0.01 to 100 mm is obtained by cutting a color-developing composite fiber comprising two or more polymer compounds having different refractive indices which are laminated alternately forming a layer capable of reflecting visible rays and interfering therewith and a layer capable of reflecting invisible rays and interfering therewith.