Purpose: The purpose of this study was to understand the meaning of the lived experience of Japanese men during the transition to fatherhood. Design: Hermeneutic phenomenology was used. Participants were 12 Japanese men who had a first-time healthy child younger than 1 year of age, who were sought by using a purposeful sampling technique. Findings: The following six themes were identified: (1) feeling like a father; (2) realizing oneself as a husband; (3) finding the wife’s pregnancy and delivery for the first time to be an impressive experience; (4) sharing time and space with one’s child; (5) being aware of a change and trying to adjust to a new life; and (6) being aware of the difference between oneself and one’s wife. These six themes created essence of the phenomenon of “becoming a father.” Discussion: This study revealed Japanese men’s own voice on becoming first-time fathers of infants.