Martin Luther`s theology was basically established on the biblical viewpoint. By the biblical viewpoint he means a grammatical and literal understanding of the Bible, that is, seeing the Bible as it is. Luther had this kind of viewpoint because the Roman Catholic theologians in the Middle Ages put human thought on the superior position to the Bible by interpreting it from the perspective of philosophy, especially of Scholastic philosophy, Luther criticized the Catholic theory of the sacrament because it was based on human reason, namely philosophy rather than the Bible. According to Luther, when we saw the Bible as it was, Christ`s presence was realized not by transubstantiation but by means of coexistence of the substance of the body and blood of Christ in and with the bread and wine (consubstantiation). Like this, Luther asserted Christ`s real presence in the sacrament, and thus he also accepted the objective effect of the sacrament. Especially, Luther emphasized it opposing to Zwingli`s sacramental view. But while criticizing transubstantiation, Luther`s contribution was to rediscover the importance of faith in the celebration of the sacrament. Luther also criticized the Catholic Church`s understanding the eucharist as good work and sacrifice. From this understanding, the celebration of the eucharist made an effect even to those who did not attend, if someone offered it for them. Finally this understanding justified to sell the indulgence. Against this understanding, Luther asserted that the eucharist could not be good works and sacrifice, but rather it was Christ`s testament. By this assertion, Luther prevented the eucharist from becoming an instrument to content human desire. In this respect, Luther did not use his criticism of the Catholic theology of the eucharist merely for the Reformation. But rather he restored the essence of the eucharist as sacrament by discovering the original meaning of the eucharist as sacrament through the biblical understanding. At this point, we can say that Luther`s criticism of the Catholic theology of the eucharist pointed out the direction of how we should see and practice the eucharist.