Tsutomu Yamaguchi, the only official survivor of both atomic blasts to hit Japan in World War II, died Monday in Nagasaki, Japan. He was 93.

The cause was stomach cancer, his family said.

Mr. Yamaguchi, as a 29-year-old engineer for Mitsubishi Heavy Industries, was in Hiroshima on a business trip when the United States dropped the first atomic bomb on the morning of Aug. 6, 1945. He was getting off a streetcar when the so-called Little Boy device detonated above the city.

Mr. Yamaguchi said he was less than two miles away from ground zero that day. His eardrums were ruptured, and his upper torso was burned by the blast, which destroyed most of the city’s buildings and killed 80,000 people.

Mr. Yamaguchi spent the night in a Hiroshima bomb shelter and returned to Nagasaki, his hometown, the following day, according to interviews he gave over the years. The second bomb, known as Fat Man, was dropped on Nagasaki on Aug. 9, killing 70,000 people.