Abstract
The purpose of this investigation is to compare the process through which men become mature fathers with their first babies and that of mothers and to clarify factors most influencing the mental development of fathers. With 178 couples, our investigation was done separately with fathers and mothers when their children had just become 18-months old. Its effective solution rate was 45.6%. The result shows that, fathers got high scores on comparatively easier to do activities such as talking to babies, carrying them in the arms, and playing with them as well as supporting their wives mentally while they made low scores on concrete child care activities and housework. Both mothers and fathers made high scores on factors concerning parental development. Both of them picked out the factor “the purpose to live” first. But from the second factors, there exist difference. As for the scores, mothers always got higher ones then fathers did. The paternal development was much affected not by how much wives expect their husbands to share housework and child care but by how much fathers' fell a sense of responsability and how they actually took part in housework and child care.
