The present report shows the analytical results of the materials used in Jiko-ji kyo held at Jiko-ji temple in Saitama prefecture. Jiko-ji kyo is a set of sutras composed of 32 volumes, decorated with gold, silver and coloring, that was produced in the Kamakuraperiod (13th century). All the sutras were restored over a period of 7 years since 2008 because many of their golden parts had peeled off and the color had changed. Nondestructive investigation using X-ray fluorescence analysis was conducted during therestoration process. As a result, both gold and brass materials were found from the parts where the golden materials had peeled off severely. Only brass materials could be found from the parts where the gold color had changed significantly. Careful judgment wasneeded to determine whether the brass found in the present analysis is original or from subsequent repairs. Up to now, it had been thought that brass began to be used after the early Edo period (16th century).Even if brass was found in a work produced before the Edo period,it was often thought that the work would be an imitation made after the Edo period. However,regarding the brass found in the present analysis,it can be judged that the brass is original because there is not any data or image to consider that brass had been used in past repairs.This analytical result shows that brass was used in the Kamakura period and in sutras.