To produce inulase from Kluyveromyces fragilis No. 351 using Jerusalem artichoke tuber extract, optimization of the condition was conducted. As results, the optimal concentration of artichoke tuber extract was 3.5% and bactocasitone showed better production than yeast extract. The optimal temperature and pH were 30℃ and 5.5, respectively. The addition of NH₄ H₂PO₄ increased the enzyme production. Inulase synthesis was growth-associated and the enzyme production increased as concentration of dissolved oxygen increased. A higher quantity of industrial grade inulase was prepared by the combination of ultrafiltration and ethanol precipitation with 72% recovery.