The second half of the 17th century has seen the development of commercial capital and in the course of that,Zaibatu,finacial cmbaines, such as the Sumitomo,the Mitsui and the Konoike emerged. For the development and lasting prosperity of the family business , they made their own family precent and instructions, which have been passed down to this day. Among those was "Monzyuin Syuisyo" (or the Family Precent written by the founder of the Sumitomo financal combine,and it has come to underlie the Sumitomo' s business sprit. The New Sumitomo Family Precent was constituted in Meiji period ,adding "Trust" , "Reliability" and "Pursuing no easy gain" to the original one - their business ethics was hereby completely establisyed. This paper first focuses on the process that the Sumitomo had taken in the course of completing their Family Precent as well as on the social and ecomonic background behind it. Based on the these researches,a discussion is made on how their Family Precent has been applied to the Sumitomo' s business in modern times.
