Abstract: A method for creating a color scale which can be used as a more objective determination criteria in order to analyze the color change characteristics of a gum with the progression of mastication of individuals with healthy teeth and jaw and to use for evaluation of masticatory performance by a color-changeable chewing gum is provided. A method for creating a color scale in which the number of times of mastication by individuals with healthy teeth and jaw and the color difference of the color developed by the gum after mastication are determined by having a plurality of individuals with healthy teeth and jaw masticate a color-changeable chewing gum to determine a regression equation of the color developed by the gum after mastication and the color difference of gums before and after mastication and further determining a regression equation of the number of times of mastication and the color difference of gums before and after mastication.