A Japanese composer Masao Ohki (1901-71) wrote his Fifth Symphony subtitled "Hiroshima" in 1953. This symphony expressed The Hiroshima Panels, a series of the collaborative works by Iri and Toshi Maruki. Ohki wrote his music for a documentary film "The Hiroshima Panels" the year before. Considering its musical relevance to his Fifth Symphony, this study reviews his musical conceptions and techniques in the film music with reference to his Fifth Symphony as follows; (1) his musical and social backgrounds, (2) artistic significance of both the panels and the film, and (3) similarities and dissimilarities in his musical techniques. As a result, it could be found that the appearances of things were expressed in similar ways; such as the force of the flames and an ominous silence of the water. On the contrary, the emotional images were expressed in different ways; such as the children in the flame and the bodies of boys and girls. Probably, it should be difficult for him to express the emotions of victims in such a catastrophe mainly because he was not a victim by the atomic bomb himself.