Cajetanus gives the two chaaracteristics of Analogia Attributionis -first, the existence of the primun analogatum in the analogy, and secondary, the designatio extrinseca from primary analogate to the secondary analogates. In this analogy of St. Thomas, there is the ontological likeness between the analogous property in the primary analogate and that in the secondary analogates. For St. Thomas, in other words, the existence of this ontological basis enables analogous property to disignate the secondary analogates extrinsically. In this paper, I intend to show the ontological basis in his analogy by the elucidation of the double designations in veritas, bonitas, ens. In the analogy of Cajetanus, the designatio extrinseca is the consequences of the conceptual operation (secundum intentionem) in the terms of the analogy, and it is extrinsic in the true sense of the words. For this reason, he defines analogia secundum intentionem solum as the anaiogia attributionis. According to him, this analogy is improper and is not given dignity as the metaphysical analogy. And he defines analogia secundum intentionem et secundum esse the analogia proportionalitatis, them we could assume that Cajetanus treated the two aspects of analogy of St. Thomas separetely, if we can see St. Thomas had taught the esse (the intrinsic ontological basis) in this analogy. But some problems prevent this assumption from being acceptable. these problems are: I) the existence of the primum analogatum in this analogy of St. Thomas, in which the analogous property is properly realized and to which the analogous property in the secondary analogates attibutes, 2) the existence of "the mixed case" in which two analogies (attributionis, and proportionaalitatis) are contained. The elecidations of this problems will lead us to another paper in which the significances of the analogia proportionalitatis in St. thomas and Cajetanus are clarified. (to be continued)