In order to clarify the enzymatic digestibility of the gelatinized starch by jastase (Japan pharmacopoeia) in Vitro, the effects of heating process (temperature and time) on the gelatinization of starch solution and storage temperature of starch gels after gelatinization, were examined. In this experiment, commercial starch of four species (potato, sweet potato, corn and wheat) were employed. The results are as follows: (1) When the starch gels were prepared at a series of gelatinization temperature (60〜110℃) at the constant heating time, the contents of glucose, produced by enzymatic digestion of them, were increased as the temperature of gelatinization was elevated, but they were almost constant between the temperature degree from 100 to 110℃ (2) In the case of employing the fixed gelatinization temperature at 100℃, the difference of glucose amounts, produced by enzymatic digestion, were negligible at the heating time more than 15 minutes. However, at the gelatinization temperature of 110℃, the contents of glucose were declined according as prolonged processing time. (3) Starch gels were prepared at a series of storage temperature (37℃, room temperature and 0〜1℃) after gelatinization at 110℃. At 37℃ storage, the relative rates of enzymatic digestibility of each starch gels were almost constant, during all the period of storage. At 0〜1℃ storage, enzymatic digestibility of them were lowered with storage time. (4) Starch gels were prepared at a series of gelatinization temperature (80, 100 and 110℃) and stored at 0〜1℃. The relative rates of enzymatic digestibility were lowered in proportion to the lowered degree of gelatinization temperature. (5) When, after gelatinization at 100℃, the starch gels were stored at 0〜1℃, the relative rates of enzymatic digestibility of potato and sweet potato starch were lowered as compared with those in corn and wheat starch.