Dumplings (Japanese Dango) with added mushroom ( Shiitake, Eringi, Maitake or Mushroom ) were produced by addition of 0.5% mushroom as dry matter to rice flour. After being kept at 25°C for 24 hrs, the hardness of the dumplings was measured. It was found that only Shiitake controlled the hardening of dumpling and the degree of gelatinization of starch measured by β-Amylase·Pullulanase (BAP) method declined gradually. These effects became more pronounced with increasing concentration of Shiitake . It was assumed that an enzyme in relation to saccharides contributed to the control of the hardening because the effect was not found when Shiitake was heat-treated. In the Shiitake dumpling, sugar composition changed and only glucose concentration increased slightly in process of time. From these results, it seemed that glucoamylase and other factors affected control of the hardening.