The present invention provides an α-glucosidase inhibitor containing a novel epigallocatechin gallate trimer and an epigallocatechin gallate polymer. Decomposition of starch derived from a meal and sugar derived from a polysaccharide can be suppressed by α-glucosidase inhibitory action, thus suppressing absorption. A food and drink excellent in α-glucosidase inhibitory action for suppressing sugar absorption and further for preventing diabetes for a long time can be provided by adding the α-glucosidase inhibitor to a food and drink.
