Junko Ishibashi was born on 22 September 1939 in Miharu, Fukushima, the fifth daughter of seven children. Her father was a printer. She was considered a frail child, but nevertheless she began mountain climbing at the age of ten, going on a class climbing trip to Mount Nasu. She enjoyed the non-competitive nature of the sport and the striking natural landscapes that came into view upon reaching the top of the mountain. Although she was interested in doing more climbing, her family did not have enough money for such an expensive hobby, and Ishibashi made only a few climbs during her high school years.