A method for purifying an oligomeric proanthocyanidin, comprising an extraction step of extracting a raw material containing multiple types of oligomeric proanthocyanidins having different degrees of polymerization with an extraction solvent selected from water and an aqueous alcohol solution, wherein the alcohol concentration in the extraction solvent is preset in accordance with the degree of polymerization of a desired oligomeric proanthocyanidin in the extraction step and the oligomeric proanthocyanidin having a desired degree of polymerization is extracted using the extraction solvent.