Bachelor in Economics, Waseda University, Tokyo, 1958. Doctor of Philosophy in Human Sciences, Waseda University, Tokyo, 1999.
Section chief Institute Developing Economics, Tokyo, 1970—1975. Associate professor Waseda University, 1975—1980, professor, 1980—2002, member executive board, since 2002. Dean Graduate School Human Sciences, Wased University, Tokyo, 1998.
Member education committee Sayama-City, Siatama, Japan, 2002.
Organizer Sayama Senior Community College, Japan, 1999. Member of Population Association American, Population Association Japan (president 2000), International Union for Science Study of Population.
Married Yoriko Nihashi Sagaza, May 17, 1965. Children: Yumiko Sagaza Ariyoshi, Tami Sagaza Kubodera.