During the 1960s worked as a journalist, writing mostly about Korean hibakusha, thus demanding from the Japanese government grant them the right to medical care in Japan.
Relatives of the dead filed a lawsuit against the Hiroshima municipality for compensations, but Mayor Hiraoka contended the city was not to blame.
His anti-nuclear activities led him to appear in 1995 as representative of the Japanese government in the International Court of Justice hearing on the legality of nuclear weapons.
[9] In December 2007 participated in a meeting with the mayor of Waitakere City in New Zealand to express protest over the whaling policy of the Japanese government.
[10] Also tried to convince both the US and the Japanese governments to allocate the funds required for the planned relocation of Radiation Effects Research Foundation facilities in Hiroshima.