To provide functional food containing chitosan and dietary fibers, wherein the chitosan does not form a complex with metal ions and/or is not connected with negative ion-charged material: and to provide a method for producing the functional food.

The functional food such as konjak is obtained through using cation-eliminated water such as distilled water or ion-exchange water. The method for producing the functional food comprises using chitosan and dietary fibers, wherein cation-eliminated water such as distilled water or ion-exchange water is used.