An intestinal environment-improving agent containing, as an effective component, a starch with a high resistant starch content that satisfies the following conditions (a), (b), (c), and (d):(a) a content of a resistant starch measured by the resistant starch measurement method of AOAC official method 2002. 02 is equal to or higher than 60%；(b) a peak of a molecular weight is equal to or higher than 6×103 and equal to or lower than 4×104；(c) a molecular weight dispersity is equal to or higher than 1.5 and equal to or higher than 6.0； and(d) a gelatinization enthalpy at 50° C. to 130° C. measured by a differential scanning calorimetry is equal to or lower than 10 J/g.
