PROBLEM TO BE SOLVED: To provide an elution reducing material which can reduce the elution of chromium, arsenic, selenium and boron and a method for reducing the elution of coal ash.SOLUTION: A heavy metal elution reducing material comprises a light burnt product obtained by lightly burning a mineral containing magnesium carbonate (MgCO) and calcium carbonate (CaCO) as main components and cement. The light burnt product contains MgCO(wherein, 0