We developed an ion exchange cellulose membrane (IEM) functionalized with tertiary amine groups. The IEM, prepared by functionalizing a base membrane with tertiary amine groups to achieve an ion exchange capacity of 0.10–0.11 meq/g, is capable of processing approximately 4 × 109 EVs/cm². Using this membrane, EVs in culture supernatants or plasma can be rapidly separated and purified within 30 minutes, without a concentration step, into EXO-rich small EVs. Importantly, this method demonstrates high reproducibility across lots while preserving biological functions, including target cell specificity and systemic circulation.