Anselm’s Ontological argument is such that when we assume a supreme being is only in our minds, we think a supreme being as it is actually, is greater than a supreme being as it is in mind, then it is impossible, so our assumption is false, therefore, is there a supreme being. Chapter II includes a flat critic of ontological argument by Kant. Plantinga summarise it as one, there is no necessarily true existential proposition, as another, existence is not a predicate. He asserts that there is at least one necessarily true proposition as ‘the succesor of 6 is larger than 5’ and, that actual existent has other contents than existent in concept, and formulate ontological argument without any entailment and supposition of predicate ‘exist’. Chaper III is to discuss a full refutation of ontological argument by Frege. It is such that Fregean existence or oneness, each expressed by existential quantifier or as a logical object one, is not generally deduced by Fregean concept or its component characteristics. Chapter IV consists of modal arguments of possible worlds theory in terms of possibilism and actualism. They seem to be failed as they stated by relational verb ‘is greater than’. In chapter V, we introduce Plantinga’s own ontological argument in terms of maximal greatness and maximal excellence, and in final Chapter VI, I suggest one contrary example against Plantinga’s.