Nobel Peace Prize winner Denis Mukwege visited Hiroshima on Saturday to pray for victims of the atomic bombing.
Congolese doctor Mukwege has been helping rape victims for many years in his African country.
He talked with 87-year-old Sadae Kasaoka at the Peace Memorial Museum. She experienced the atomic bombing at the age of 12.
Kasaoka said the world would come to an end if a huge number of nuclear weapons were used. She said she wants many people to work for the elimination of nuclear arms, not just reducing their number.
Mukwege pledged to serve as an ambassador in relaying her message to the world.
He then toured the museum, which features a georama of Ground Zero along with victims' personal belongings. He wrote in the visitors' book that nuclear arms must be abolished.