Based on our previous work, this paper discusses IT utilization by long-established Japanese companies and its effects. According to our interviews to some managers of such companies, IT systems have been actively introduced and have shown positive effects. For example, multiple numbers of long-established Japanese-style confectionary companies in Kyoto such as Wakanaya and Fujikoma, a soba noodle restaurant which has more than 200 years of history, told us during the interviews that their sales increased approximately 10% after they started online sales. Also, after using IT systems for recruitment, they started to receive more inquiries than before both domestically and from abroad, and now they feel it is easier to obtain competent human resources. As mentioned above, IT seems to have a positive impact not only on the profit side but also on various aspects. Management studies have discussed business growth so far, but study on business continuance and decline has been only narrowly kept going. Therefore, we will examine here comprehensively covering business continuance and decline using business system theory. We provide the overview of several long-establish companies upon which our study is based, including Kongo Gumi, Chidoriya, Wakanaya, Yasuda-Nenju, Chuuboku-Chaya and Fujikoma.