A novel imidazole derivative type reagent for analysis of hydrogen peroxide, a method of analysis of hydrogen peroxide using the same, a method of analysis of peroxidase using the same, and a multilayer chemicalanalytical element containing the same are disclosed.The imidazole derivative has the formula (I): ##STR1## wherein R.sup.1 and R.sup.2 represent an aryl group or a substituted aryl group, and R.sup.1 and R.sup.2 are identical with or different from each other, and R.sup.3 represents 2- or 3-pyrrolyl group, a substituted 2- or 3-pyrrolyl group, 2- or 3-indolyl group, or a substituted 2- or 3-indolyl group.