The main question of this paper is: "What is the criterion in Ontological Argument (Burhane Siddiqin)?" This question can be analyzed into three questions as fallow: (1) what are the characteristics of this argument? (2) Which characteristics are to be considered as the criteria of it? (3) Which characteristics are to be considered as the advantages of it? This paper aims to answer these questions and comes to the conclusion that there are five characteristics for this argument:1. The Necessary Being is to be proved by considering the existence.2. The argument must produce the same result even if possible existents are denied.3. The argument must be independent of the proof for the impossibility of the vicious circle and the infinity regress.4. Real and actual attributes are to be used in this argument.5. The argument is not influenced by the acceptance of possible existents or the rejection of them. Having read the paper, one will find that the first and the second characteristics are together the criteria of the mentioned argument, and the third is not relevant to it, while the fourth and fifth ones are the advantages of it.