He had two elder brothers; Yoshiki OGAWA (a metallurgist and the professor of the University of Tokyo) and Shigeki KAIZUKA (a scholar of Oriental history, the professor emeritus of Kyoto University, and a winner of the Order of Culture).
兄小川芳樹（冶金学者・東大教授）、貝塚茂樹（東洋史学者・京大名誉教授、文化勲章受章）