From the « annunciation to the husband » (You are going to be a father, I’m expecting your baby), through birth, to the first weeks of the baby’s life, the father who is also the mother’s companion is too often forgotten, in terms of what he is experiencing, his functions and the specific psychical upheaval the work of fatherhood entails. This research portrays the three principle phases of becoming a father and the different registers that modulate the paternal partition.