Traditonally, Descartes’s ego that implicit in hi primary metaphysical principle-cogito ergo sum-, has often been interpreted through Heidegger’s view. His interpretation considered Descartes’s ego as a being to dominate the world through the representing activity. Some postmodern philosophers are based on Heidegger’s this point. So such thinkers are aimed at overcoming Descartes’s theory of the subject. Is such an understanding justifiable? I disagree strongly with it. So in this paper, main idea is to criticize Heidegger’s such interpretation of Descartes. In this regard, we must rely on the French Philosopher Jean-Luc Marion to embody our theme. Marion has re-read Descartes’s Passions of the Soul. Beyond mere reading, through his reading of the Passions of the Soul, Marion has interpreted not the primary metaphysical principle but the ego of auto-affection concerning Descarte’s ego. According to Marion, ego become an existential being with an ethical-axiological aim by his auto-affection. The ego is no longer a subject who represents the world. In this interpretation, Descartes’s ego cannot be understood only as a metaphysical subject. Thus this ego must be recognized as an existential-volitional ego with axiological aims. Throughout this study, we will encounter with a new understanding of Descartes’ ego.