The present article refers to the maternal function in the mother-infant early bond from Donald Winnicott’s psychoanalitic point of view. This author, authorized since he was a pediatrician and a psychoanalitic doctor, was capable to see the prematurity of the human baby and the affective state of the mother function before the child’s birth. The needs of the newborn and his mother far from being complementary have their specificity that make necessary to consider the holding function that is expected from the mother. This work addresses the dimension of the reality as a limit and an organizer of the psychism in the early mother-baby relationship. The author works this topic from the paradigm of the building of a space that takes place in the mutual dynamic. She analyzes the illusion and disillusion function to build a possible destiny for the maternity and in the transition of the baby to the autonomy of a new person. When it’s said about "the primary", it is in the sense of the time of building the psychism. A relational time, as Winnicott says, in which when we find an infant, we will always find the maternal care.