The invertase (EC 3.2.1.26), which catalyzes the hydrolysis of sucrose, has been purified 71-fold from Jerusalem artichoke tuber. Electrophoresis showed that the native enzyme is consisted of single polypeptide chain of 86,000 daltons. Optimum pH and temperature for the enzyme action were pH 7.0 and 40℃, respectively. The enzyme exhibited high hydrolytic activity to sucrose, but no activity on inulin. The enzyme had an apparent Km of 24.7 mM for sucrose.