An indigestible dextrin characterized in that the dextrin contains: (A) up to 50% of 1-> 4 glycosidic linkages, and (B) at least 60% of an indigestible component, (C) the content of indigestible component as actually determined varying within the range of +/-5% from a value Y calculated from at least one of equations, i.e., Equations 1 to 62, given in the specification, (D) the indigestible dextrin being prepared by adding hydrochloric acid to corn starch and heating the corn starch at 120 to 200 DEG C using an extruder, the value Y being a calculated content (%) of the indigestible component.