A period indicator including a liquid-permeable substrate and an indicative section which is overlaid on a portion of the substrate and which is formed from a liquid-permeable material having a low light refractive index, the indicator containing a volatile liquid, wherein the indicative section is formed by coating a surface of the substrate with an indicative-section-forming material prepared by mixing a binder and finely divided particulate matter having a low light refractive index, the indicative section is composed of two or more regions, and the regions differ in height from one another as measured from the surface of the substrate, as the coating amounts per unit area of the indicative section forming material in respective regions differ from one another. Since the period indicator can indicate the chemical-containing state stepwise, it is useful for indicating the available period of use of a chemical such as a mothproofing agent, an insecticide, a deodorant, or a fragrance.