Nonaka was born on 25 July 1905 in Ashoro, Hokkaido as the eldest child of Masujiro Nonaka and his wife Kiyo Nonaka, and had two brothers and three sisters. In his youth, Nonaka worked as a farmer and lumberjack until 1925 when he took over Nonaka Onsen, a hot spring inn founded by his parents in 1905 and nowadays owned and managed by one of his grandchildren. In 1931, he married Hatsuno Nonaka, who died in 1992 and with whom he had 5 children (2 living).